CHAPTER VII. The Spur and Crural Gland

THE SPUR AND CRURAL GLAND

In both platypus and echidna there occurs on the inner side of each hind limb of the male a movable spur. This is found in the young female also; but in the full-grown female it has disappeared, leaving a depression to mark the spot where it had been. This condition suggests that the spur and depression are of the nature of secondary sexual characters, and have something to do with reproduction. Such was the general belief for twenty years after the first discovery of the platypus. Then it was reported from Australia that the spur of the male was capable of causing serious wounds, followed by dangerous symptoms due to a venom expressed through the spur. Thus began a lengthy controversy which has not yet been settled to the satisfaction of all.

Shaw (1799) described the spur as a sixth digit, but pointed out that it resembled a strong, sharp spur. Home (1801, p. 72) made the first surmise as to its function, and described it in the following terms:--

“In the male, just at the setting on of the heel, there is a strong crooked spur, half an inch long, with a sharp point, which has a joint between it and the foot, and is capable of motion in two directions. When the point of it is brought close to the leg, the spur is almost completely concealed among the hair; when directed outwards, it projects considerably, and is very conspicuous. It is probably by means of these spurs, or hooks, that the female is kept from withdrawing herself in the act of copulation, since they are very conveniently placed for laying hold of her body on that particular occasion. The female has no spur of this kind.”

In March 1817 extracts from a letter from Sir John Jamison, dated at Regentville, New South Wales, September 10, 1816, were read before the Linnean Society of London and published in the Transactions for 1818 (pp. 584-5). Jamison writes:--

“I cannot avoid relating to you an extraordinary peculiarity which I have lately discovered in the Ornithorhynchus paradoxus. The male of this wonderful animal is provided with spurs on the hind feet or legs, like a cock. The spur is situated over a cyst of venomous fluid, and has a tube or cannula up its centre, through which the animal can, like a serpent, force the poison when it inflicts its wound. I wounded one with small shot; and on my overseer’s taking it out of the water, it stuck its spurs into the palm and back of his right hand with such force, and retained them in with such strength, that they could not be withdrawn until it was killed. The hand instantly swelled to a prodigious bulk; and the inflammation having rapidly extended to his shoulder, he was in a few minutes threatened with locked-jaw, and exhibited all the symptoms of a person bitten by a venomous snake. The pain from the first was insupportable, and cold sweats and sickness of the stomach took place so alarmingly, that I found it necessary, besides the external application of oil and vinegar, to administer large quantities of the volatile alkali with opium, which I really think preserved his life. He was obliged to keep his bed for several days, and did not recover the perfect use of his hand for nine weeks. This unexpected and extraordinary occurrence induced me to examine the spur of the animal; and on pressing it down on the leg the fluid squirted through the tube: but for what purpose Nature has so armed these animals is as yet unknown to me.”

Blainville, also in 1817, described the canal in the spur and the cyst at the base; as the specimen he examined was a skin only, he did not find the gland. In the Edinburgh Philosophical Journal (vol. vi, 1822, p. 184) it is mentioned that Dr. Traill confirmed the existence of a canal through the spur, so small that he could not pass a horse-hair through it, though a human hair passed.

In the same year an extract of a letter from Mr. Patrick Hill, Surgeon in the Royal Navy, dated Sydney, 3rd January, 1821, and addressed to the Secretary of the Linnean Society of London, was read before the Society and printed in the Transactions for the year, pp. 622-4. Hill writes:--

“You will be gratified to learn, that I have been completely successful in establishing our friend Sir John Jamison’s account of the spur of the Ornithorhynchus paradoxus. I subjoin an extract from my notes:

“Sunday, Oct. 1, 1820--On the banks of Campbell’s River. In the morning shot a male Ornithorhynchus. On examination, soon after it was killed, I observed near the extremity of the convex side of the spur, a minute spot, like the orifice of a tube; and on endeavouring to pass a bristle from this spot, three successive drops of a limpid clear fluid issued from it. I then examined the other spur with the same result. On dissecting the foot of the animal, I found at the inner side of the root of the spur, immediately over the articulation, a small cyst, which I cut into; it did not at that time contain any fluid; but from it I, with great ease, passed a horse-hair through the spur. This preparation I have sent to you, together with the dried cyst.”

Farther on he quotes Cookoogong, chief of the Boorah-Boorah tribe, as being “perfectly aware that a wound from the spur of the male is followed by swelling and great pain; but although he has seen many cases of it, he has never known it fatal.”

Knox (1823, p. 38) describes and gives the first published figure of the gland, duct, cyst, and spur in situ in a dissection of the leg. He opposes Home’s views as to the copulatory function, and is of opinion that the spur must be a weapon of offence. In the same year Home records the presence of the gland, and describes how Clift passed mercury through the duct--an experiment which Knox also performed. The specimen examined by Knox has a certain historic interest, it having been sent to the Royal Museum of the University of Edinburgh by the then Governor of New South Wales, Sir Thomas Brisbane.

In an anonymous article in the Annales des Sciences Naturelles (ii, 1824, pp. 75-6) from which I have previously quoted, the statement is made that Jamison first announced the perforation of the spur, that Van der Hoeven could not find it, but that Meckel confirmed its existence, as well as that of the gland, in a letter to Brechet, the editor of the Annales.

In 1826 Knox recorded the presence of a rudimentary spur in the female echidna, and claimed that this discovery disposed of Home’s suggestion of a copulatory function.

Isidore Geoffroy’s article on Ornithorhynchus in the Dictionnaire Classique d’Histoire Naturelle, published in 1827, refers to a publication by Dr. Parmeter in Sydney:--“Cet auteur établit que les mâles emploient leur ergots pour tenir les femelles immobiles dans l’acte de la copulation, et il a publié sur ce sujet un petit Mémoire imprimé dans la Gazette de Sidney.”

Dr. Parmeter was in practice on the Hawkesbury River, and must have had opportunities of observing the platypus, which was then so plentiful there. A weary search through the pages of the Sydney Gazette brought to light only two occurrences of his name, apart from casual attendances at the inquests which formed so prominent a feature of the early days. One of these is at the foot of an advertisement deploring the fact that his patients were not paying their bills, and threatening drastic action unless they mended their ways; the second was the advertisement of a forthcoming publication, The History of Australia by T. Parmeter, M.D., with a list of a few advance subscribers--but it would seem that the work was not published. In the Gazette of December 4, 1823, there does, however, appear a letter, signed “Observator,” which is almost certainly the memoir referred to.

Like most early statements about the platypus, it contains more conjecture than observation. It is a comment on an excerpt concerning Knox’s dissection of the spur and gland which had appeared in a previous issue. Parmeter says:--

“I take leave to remark, that I have dissected this animal particularly, to ascertain this much controverted point, and have not been able to trace, either in the living or dead animal, the virus supposed to be contained in the sac; and I am not solitary in my opinion, that there is no poison; nor is it, properly speaking, a gland, which the spur is conjoined to.... That the plectrum answers the particular purpose of a prehensile, is more rational to conjecture, than that nature should have furnished the male with a weapon (offensive or defensive), and not similarly provided the female.”

This can scarcely be said to justify Isidore Geoffroy’s statement that Parmeter has established the fact that the males employ their spurs to hold the females. Further on in Parmeter’s letter the following lines occur:--

“I therefore invite any Member of this infant Association to correct me, from an authenticated fact, of any individual having been injured from the wound of this animal’s spur.”

This, from a medical practitioner who lived for many years among the farming community on the banks of the Hawkesbury at a time when the platypus was notoriously abundant in that river, and yet who had never known of a case of injury from its spurs, points to the great rarity of such an occurrence. The reason is that fully ninety per cent would be drowned in the fish-nets, and the remainder killed before being handled.

In 1829 there appeared in the Edinburgh New Philosophical Journal a letter from Thomas Axford, Esq., dated from Thorpe, Tasmania, 30th June, 1828. He writes (p. 400):--

“It is my firm conviction that the animal has not the power of instilling poison by its spur; and I believe this appendage is used principally for securing the female in the season of love, though it may also be useful in enabling the animal to climb the steep banks of rivers. I have taken several large females, and I suppose old ones, with the hair worn off, and only the fine fur left on their rump; and although I have killed very large males, never found one in that state. The moment I saw the first old female thus denuded, it struck me that the denudation must arise from the action of the spur of the male in holding the female.”

Verreaux (1848, pp. 130, 133) stated that the spurs were used to hold the female in copulation, being applied to her posterior part; and that, though he had handled many male platypus, none had ever attempted to use its spurs as weapons of offence against him. Dr. Bennett records the same experience. He endeavoured (1860, p. 107) to incite the animal to use its spurs, placing it in a variety of positions, and teasing it to make it angry, but without success. He was convinced that the spur was not used for offensive purposes. Krefft (1871) writes:--

“It is possible that the spur has some poisonous properties during certain seasons of the year, because we remember being cautioned to handle a male Water-mole, by a gentleman who said that he once had been wounded in the arm by one, and had suffered severely in consequence.”

Spicer (1876, pp. 162-3) records the case of Mr. Augustus Simson, of Gould’s country in Tasmania, in a communication read before the Royal Society of Tasmania on 13 November, 1876:--

“About three weeks ago, he and Mr. Stephens, the School Inspector, were walking by the side of a lagoon, when their attention was attracted by a Platypus, which had swum across from the other side, and was on the point of making its way under the bank. Mr. Simson, an active, energetic man, at once rushed down the bank, and secured the animal. Now, I fancy, this fact alone is worthy of record; for of all the shy wary animals in existence, Platypus is amongst the shiest and most wary. Under ordinary circumstances, it is no easy matter to catch even a passing sight of one; but here the creature was caught in open daylight....’ The platypus was put safely in a bag, but escaped. Mr. Stephens now takes up the story:--

“After an exciting chase, Platypus was recaptured; but this time he revenged himself by giving my friend a severe wound on the hand, one spur slightly tearing the palm, and the other the back of the hand, making a deep puncture between the knuckles of (I think) the first and second fingers. The pain from this was intense, and almost paralysing. But for the administration of small doses of brandy, he would have fainted on the spot. As it was, it was half an hour before he could stand without support. By that time the arm was swollen to the shoulder, and quite useless, and the pain in the hand very severe. No ammonia was to be had; no medical assistance was available; and the only treatment that could be adopted, was to keep the whole arm for a night and a day in wet bandages, which seemed to alleviate the pain a little, and to reduce the inflammation.

“A week later I was informed by letter that the swelling had subsided, the hand being still very tender, with a sensation as of a severe bruise. From this time there was a slow but gradual improvement.”

A letter from the victim substantiates this statement, and he adds (p. 163):--“Some natives tell me they would rather lay hold of a snake than a Platypus.” On the same page Stephens describes the mode of attack, which was precisely the same in this case as in that described by Jamison:--

“The mode of attack is not by scratching, but by a powerful lateral and inward movement of the hind legs, the spurs being thus brought together like the points of a pair of callipers.”

The late Professor Sir Anderson Stuart, of the University of Sydney, records further cases of poisoning in his Presidential Address to the Royal Society of New South Wales, published in the Society’s Journal for 1894. His account, which occurs on pp. 5-9, is as follows:--

“I have no doubt whatever that it is, at least at certain seasons, a powerful poison. I have from time to time made enquiry, and have also advertised for information, and I have two good accounts from very intelligent hunters of the animal, in widely separated parts of the Colony, which coincide perfectly, so that I have no doubt myself that they accurately represent the main features of the action of the poison in dogs and as observable by laymen.

“One account shows that the males fight very fiercely while in the water during the pairing season, mostly applying themselves to each other belly to belly. The scratches are mostly on the under surface of the tail. The females are very seldom found scratched. One of the hunters tells of a dog he had which was ‘stung’ on three different occasions--each time both spurs were employed, and the wounds were always on the dog’s cheeks. The wounds are always described as on the head or face somewhere, because they are inflicted while the dog is retrieving the wounded animal. The effects followed very quickly, like the sting of a bee. Within a couple of minutes the head began to swell, and on the first occasion had reached a ‘tremendous’ size within a quarter of an hour. This swelling gradually disappeared, and was gone in thirty-six, ten, and three hours on the first, second, and third occasions respectively. The swelling and all the other symptoms were less marked the second than they were the first time, and the third than the second time. The swollen head was tender to touch, for the dog ‘sang out’ when it was touched there. The eyes were at first closed up by the swelling, and when again visible were ‘wild-looking.’ The dog became sleepy, as if under the influence of a strong narcotic, so that he had to be carried to the camp, and he moaned from time to time. The dog would neither eat nor drink, but there was no salivation, vomiting, diarrhoea, tremor, convulsions, nor staggering. Breathing was difficult, but not very. This dog quite recovered.

“My other account is from one of two brothers who were both great hunters of platypus, and he confesses to having been wicked enough to have shot many thousands during his thirty-two years of work. He had four valuable water-dogs that died from the ‘stings.’ On one occasion he actually saw the platypus strike, heard the dog whine, saw the wound, and the train of symptoms ending in death. These were comparatively large dogs. He knew that after he himself gave up hunting, his brother, who went on with it, lost dogs too. The drowsiness was so intense that he has had to carry the dogs on horseback with him for as long as three hours.”

Here follow details of the accounts given by Jamison and Spicer, which are quoted above. Anderson Stuart sums up (p. 9):--

“Now if we review these four accounts, we note that--

“1. They are all absolutely independent, not one writer knowing anything of the other three, three hailing from different parts of the colony of New South Wales, and one from Tasmania, and all from different periods of time.

“2. Two were in the human subject and the rest in dogs.

“3. The train of symptoms, mutatis mutandis, agree most perfectly.

“4. In all cases the poison was allowed to follow its natural course, nothing but external applications, if anything at all, being ever employed by way of treatment.

“5. The symptoms were specific, and differed entirely from the ordinary surgical effects of lacerated wounds.”

He concludes that the gland secretes a powerful poison at certain seasons, probably during pairing-time.

Martin and Tidswell (1894) made a chemical examination of the fluid secreted by the crural gland, and an inquiry into its physiological effect when injected into rabbits. Their paper gives an excellent summary of the history of the controversy, and mentions cases of poisoning other than those given above. Thus on p. 476:--

“Under the heading: ‘The Poison of the Platypus’, the following extract from the Maitland Mercury is quoted in the Australian Journal of Education (1869):--‘On Tuesday, the 9th instant, when Mr. E. was fishing in the river near his residence, he found that a Platypus had got entangled in the net, and upon catching the animal it immediately struck the two spurs attached to its floats or arms into the forefinger of Mr. E.’s left hand, with such force that they penetrated through the skin and into the muscles of the finger, and it was with great difficulty that Mr. E. at last succeeded in ridding himself of his unwelcome intruder and eventually killed it. Mr. E. all the time suffered intense pain, and presently the wounded finger, then the hand, and ultimately the whole arm up to the shoulder swelled to a serious extent. The symptoms usually following snake-bite also set in, and after a day or two Mr. E’s state became so serious as to alarm his friends for his safety, and Dr. G. having been sent for, he applied ammonia and the usual remedies against snake poison, and we are glad to learn that Mr. E. has now entirely recovered.’”

On p. 479 Martin and Tidswell quote A. Nicols (Zoological Notes, London, 1882, p. 116):--

“A. Nicols records having wounded and captured a Platypus which was lively enough to scratch him with its sharp claws, but made no attempt to use its spurs when handled. The native who accompanied him, however, expressed fear of the spur. Nicols thought that the spur and its gland might be ‘a remnant of conditions of life very different from those under which the animal now exists.’ He considered that, although it might possibly be used in contests with its own kind, ‘there is no reason for attributing a poisonous character to this weapon.’”

On p. 480 the authors mention four more cases (two in men and two in dogs) recorded by Dr. Lalor in a communication abstracted in the British Medical Journal for June, 1894, p. 1332. There is thus a considerable body of evidence for the poisonous nature of the secretion.

Martin and Tidswell proceed (pp. 482-487) to an examination of the anatomy and histology of the gland and duct, which they figure on their Plate XXVIII. The glands are more or less kidney-shaped bodies, with the concave border outwards, symmetrically disposed on either side of the vertebral column above the acetabulum and femur. Each gland lies in a special compartment of the deep fascia, covered by the panniculus carnosus and skin, between the muscles of the leg on the outer side, and the gluteus maximus on the inner. An average gland measures 3 cm. in length, 2 cm. in breadth at its widest part, and about 1.5 cm. in thickness. The surface is lobulated.

The duct emerges from the posterior half of the outer border, and passes downwards, with the nerves and blood-vessels, on the posterior aspect of the leg. It measures about 5 cm. in length, and, in an undilated state, about 2 mm. in external diameter. After leaving the gland it passes down under the biceps muscle, crosses the tendon of the gastrocnemius, and reaches the spur. Here it becomes dilated into a sac, which is so deeply embedded in the ligamentous tissue at the back of the tarsus that its isolation is a matter of difficulty. From this dilation a prolongation extends into the canal in the spur, which is attached to a supernumerary tarsal ossicle, articulated to the astragalus and tibia.

The gland is enclosed in a capsule consisting of an outer layer of unstriped muscle, three or four cells deep, and an inner coat of white fibrous tissue, which is continued into the mass of the gland as a stroma separating the alveoli. It is of the compound racemose type. The duct, traced into the gland, divides repeatedly into smaller and smaller branches; the final branches open into the alveoli, which are dilated, and lined by a single layer of epithelial cells situated upon a basement membrane.

Sections across the duct show that it possesses a single lumen close to the spur, which becomes multiple as it is traced backwards towards the gland. The wall is composed of fibrous tissue, without any muscular elements whatever, and is lined by an epithelium composed of four layers of cells. The saccular dilatation at the base of the spur has the same structure.

The fluid secretion, which is described as ‘limpid and opalescent’ by Martin and Tidswell, was chemically examined, with the following result (p. 490):--

“Our conclusions as to the composition of the secretion drawn from the above experiments are:--

(1) It is a solution of proteids.

(2) That the greater portion is composed of a proteid belonging to the class of albumins, and that in addition a small quantity of proteose is present.

(3) Nucleo-albumins are absent.”

The authors remark that the toxicity of snake venom is known to be due to its proteose content; but in their experiments with the platypus fluid, because of the smallness of the quantity of material available, it was not possible for them to separate the proteose from the albumin. Consequently the limited number of experiments which were possible had to be made with the mixture.

Experiment I: A rabbit had .05 gramme of the ‘poison,’ dissolved in 5 cc. of .75-salt solution, injected under the skin of the abdomen. Upon the following day a swelling the size of a duck’s egg had appeared near the seat of the injection, which was tender to the touch. The animal was sick, with dull eye, eating sparingly, and its temperature had risen by one degree Fahrenheit. A day later, the swelling and temperature were reduced, the animal was much livelier and taking food. In a couple of days more it had completely recovered.

Experiment II: 6 cc. of a solution of the dried poison in .75-salt solution, of such strength that the dose actually contained .06 gramme of the actual gland secretion, was injected through a cannula into the jugular vein of an etherized rabbit. The experiment was arranged so that a simultaneous record of blood-pressure, respiratory movement, and time-rate was recorded upon a revolving drum covered with smoked paper. Within three seconds from the commencement of the injection the blood-pressure fell by 40 mm. of mercury, the heart-beats becoming less frequent. At the same time the respiration became hurried and exaggerated, and speedily terminated in a series of expiratory convulsions, in the course of which the blood-pressure rose again, but speedily fell. In a minute and a half the animal was dead. An immediate post-mortem disclosed that the right side of the heart and the whole of the venous system were full of clotted blood; the left chambers of the heart and the pulmonary veins contained fluid blood, and there was an extensive endocardial haemorrhage. Martin notes that this condition is precisely similar to that induced in rabbits by the intra-venous injection of snake venoms.

Two further experiments were made similar to the latter of the two above, but with smaller doses of poison. The dose for Experiment III on p. 494 of the paper is given as 0.4 gramme, but this obviously should read 0.04 gramme. The former quantity was equal to the total amount of poison held by the investigators (see p. 496). Experiment III gave the same ultimate result as Experiment II, but at a slower rate; in Experiment IV the blood was not clotted, but on being drawn off coagulated at a rate much slower than the normal.

The authors claim that these experiments prove the secretion of the gland to contain some body capable of producing very considerable toxic action when introduced into the bodies of rabbits. They admit that this toxic agent may be of other than proteid nature, but do not think it likely, since the results resemble those produced by proteid poisons. The whole of the experiments, including the apparently contradictory result obtained in Experiment IV, show a close agreement with results obtained by use of snake venoms. The venom of snake is, however, 5000 times as virulent as the preparation of platypus poison used. The latter appears to be much more powerful in the production of local oedema.

Their final conclusions follow (pp. 498-9):--

“At the conclusion of our survey of the literature of this subject, we pronounced the opinion that as far as the evidence adduced went, it presented a very strong case in favour of the contention that these glands, at any rate at some seasons, produce a poisonous secretion.

“We venture to think that the results of our experiments have established the fact that the secretion is poisonous at some time of the year. Whether the animal is capable of discharging a secretion possessed of poisonous properties at all seasons of the year is not at present determined. Creighton states definitely that the gland is subject to seasonal variations in size just as is the case with the mammary gland and testes (Bennett). We have been unable to find on what evidence Creighton makes this statement; but the differences in minute structure observed by us lend support to this view.

“The idea naturally occurs to one that this apparatus, which is confined to the male sex, owes its peculiar development to the operation of sexual selection. That it is a weapon used by the males on one another when conflicting for the possession of the females, is an idea which would become extremely probable if it could be established that the gland is specially developed at or about the pairing season. This is a point which could be settled without difficulty, provided specimens could be obtained in sufficient number at suitable periods of the year, say August and February.

“Bennett found developing ova in the uterus as early as September, so that in all probability the animals pair during the latter part of August and earlier part of September.

“That the secretion obtained by us from the glands of an animal killed in June proved actively poisonous, whilst that from an animal killed in April was innocuous, is interesting in this respect, although June would indicate a somewhat early preparation for pairing. We cannot, however, place much stress on this isolated observation, as it is quite possible that the difference in development was due to quite other causes. In the meantime the biological significance of these extraordinary organs must remain an open question.”

The following interesting measurements and dates were recorded by me after dissecting three robust adult male platypus during the rut of 1923.

Testes Crural Macdonald River, N. England, 8-10-’23 7 × 10 mm. 9 × 20 mm. Namoi River, Manilla, 10-10-’23 22 × 30 mm. 15 × 44 mm. Namoi River, Manilla, 23-10-’23 5 × 10 mm. 8 × 20 mm.

The last two males were taken in the same locality.

Although I omitted to measure the scent-glands, I observed that their size was in proportion to that of the testes and crural glands. This, then, suggests to me sexual affinity, so to speak, between all three sets of glands in or out of season, and furthermore, that such conditions prevail until all are gradually exhausted. This may occur late or early during the rut, according to circumstances.

An aboriginal once informed me that he had seen the male platypus carrying nesting-material by means of its spurs. I do not, however, put much trust in this story, for, so far as I have observed, the female builds the nest unaided. As regards bachelor quarters (even during the cold months), all the males that I have unearthed to date were in cavities of bare earth.

We have, then, a mass of evidence, contradictory in nature, yet adduced by competent observers. It will be of interest to summarize the suggestions which have been put forward as to the function of the spur, and to see whether the apparent contradictions cannot be reconciled. The suggestions made are five in number:

(1). That put forward by several early naturalists (e.g. Axford), that it aided the animal in climbing banks. This may be dismissed without further comment, for it is quite obvious that the female has greater need of bank-climbing apparatus--if such be necessary at all--than the male.

(2). The suggestion by Baden-Powell, quoted by Spicer, that the secretion is simply a dressing for the fur, a function which, it will be remembered, Geoffroy Saint-Hilaire once suggested for the mammary gland. Here, again, if an oil for the fur be needed, the need of the female is as great as that of the male. Moreover, although the hair is combed principally by means of the claws of the hind foot, the spur is not suitably placed for assisting in the operation.

(3). The suggestion of Nicols, quoted by Martin and Tidswell, that the spurs are a remnant of conditions of life very different from those under which the animal now exists. Martin and Tidswell remark (p. 480) that, while it is very difficult to show that the suggestion is false, it does not appear to be reasonable. A complicated arrangement, in a condition of functional perfection, would hardly be retained if it were of no service to the individual or the species. With this I agree.

(4). The position taken by Jamison, Knox, Spicer, Martin and Tidswell, and others, that the spur and gland are weapons for the infliction of poisonous wounds, either upon other males when fighting for possession of the female, or upon enemies in general. The evidence for seasonal variation in the functional activity of the gland is definite enough, but is insufficient to rule out the notion that the spur is a weapon of offence against enemies in general. The demand for protection from enemies is not seasonal; it is an affair of all the year round, and the spur is dangerous at all times.

As one of the uses of the spur is almost certainly to inflict poisonous wounds, it is probably directed against other males of its own species as well as against natural enemies. One other observer besides myself (Verreaux) has claimed to have seen the act of mating. Here at least I have confirmatory evidence that this act takes place in the water. As to whether Verreaux’s description of the event is in every particular correct or otherwise, I am not concerned. There is, of course, no doubt that the secretion, when introduced into the blood-stream of a mammal, has a powerful toxic effect, and Martin and Tidswell claim no more than this. When two males fight, I judge from the position which they take up at first that the introduction of the venom is designed by both combatants. Combats among mammals for possession of the female are rarely fought to the death. They are, admittedly, at times severe, but are tests of physical strength and endurance, in which the weaker goes to the wall with nothing more than a few wounds. I have known platypus males placed together in confinement disagree with, and sometimes kill, one another, though I have no evidence that death was caused by poison from the spurs. But I have always thought that such might be the case.

Before solving the problem of keeping platypus in captivity for exhibition purposes, I handled many freshly-trapped uninjured males, first while collecting, and later with specimens imprisoned in a contraption which I termed, at that time, a “Platypusary.” Realizing that the less handling the animals received, the better for the test, I did not ruffle their tempers more than was necessary. Not once during manœuvrings did a male make any attempt to use his spurs on me. I naturally came to the hasty conclusion (as others have done) that male platypus are ridiculously docile, good-tempered creatures.

Since then my opinion of them in this respect has changed, and for this reason. I placed two freshly-caught adult males together (in the breeding-season) in a large tub half-filled with water. After several endeavours to crawl up the sides of the tub--which I prevented them from doing--they became enraged, not only with me, but, apparently, with themselves and one another. Presently a quarrel began in earnest; they were floating side by side at the time, each with its head to its opponent’s tail. As they became more and more tightly pressed together for their full length, they circled around as one centrally-pivoted concern. This was caused by each combatant, with gaping jaws, strenuously endeavouring to catch hold of the other’s tail at the tip. Each in turn eventually succeeded and hung on tenaciously as though all depended on this remarkable grip. Both seemed so concerned that now my presence appeared to be unheeded. Wriggling and paddling began with vim, presumably with the object of one turning the other over without being overturned itself. Had this fight been waged in deep water, it is difficult to imagine what advantage either would obtain over the other. Ultimately there was a great splash, and the antagonists were in firm holds, heads to tails, for their full length, beneath the water; but on bumping the foreign bottom they instantly released their holds and came to the surface for a blow. As I could not induce them to battle again, I released them into the Namoi River.

It is worth noting here that, while under water in the locked position as described, the vital external jugular veins of each (mentioned by Martin and Tidswell) would be exposed, and nothing less than a timely parry with the versatile fore-paws would suffice to prevent a death-dealing puncture, if not actually in the jugular vein, then in close proximity to it. In any case, if this did occur it could hardly be called accidental. As in the case of all fauna in a fight to a finish the combatants would probably receive many wounds in different parts before one was totally disabled.

This, then, brings me to another point. If the “dope” (as I term it) is not of a deadly nature during the mating session, why is it always ejected by the animal when it deliberately spurs at an enemy? Hoy’s encounter with an infuriated male in the height of the breeding-season convinces me that the secretion is used for offensive rather than for amatory purposes.

Before placing the males together in the tub I experimented with the larger of the two (weighing exactly four pounds) purposely to explode my initial theory that males will not intentionally use their spurs when being handled. Of course, I knew the truth even then, but I required sufficient proof to satisfy the most sceptical. This is what occurred: I first placed a special rubber gauntlet over my right forearm, then gloved that hand adequately, leaving my left free for minor purposes. After placing the robust male platypus on a table, abdomen uppermost and tail towards me, with my bare hand I held the wriggling creature by the head. Then, to exasperate him, I placed my right arm on his tail and deliberately tantalized him by tickling him from back legs to brisket with my fingers. Several times he raised his spurs simultaneously as if sparring for a grip, but each time lowered them again. Tiring of such monotonous behaviour, I removed my arm to rearrange his position and to reverse my hand-holds temporarily. But, while I was bringing my bare hand back to grasp his tail, the platypus, as though aware that I was off my guard, like a flash struck with his spur and ripped the edge of my left hand for a distance of over an inch towards the little finger. This action was so quick and unexpected that it certainly gave me a shock. After placing the platypus back in the box, I repeatedly squeezed the wound and made it bleed very freely.

My wife then took a hand, and flooded the wound with iodine twice within half an hour; each time she did so, the pain was acute in the extreme--far more so than when first inflicted. The rip, which was jagged by my tearing away from the temporarily rigid spur, was 1⅛ inch in length, and ⅛ inch in depth. Now, whether the pulling away of my hand simultaneously with the striking of the spur saved me from receiving a full dose of dope, or any at all, is questionable. But two or three days later, when I had almost forgotten the event, I felt a slight pain under the arm, and noticed a redness leading thereto from the wound. Nothing more serious developed; but it occurred to me that, as the iodine entered the wound, so the secretion administered with the prod of a spur, during conflict, although not a deadly poison, might at any rate cause sufficient pain, when injected into a wound, to cause the rival at once to desist. If so, nothing more is necessary when duelling for possession of the gentler sex.

While on this subject, I will explain why and how the platypus is capable of inflicting very severe wounds with its spurs. When the animal is not anxious or prepared to grip, the spur may be lifted back with one’s thumb and forefinger. This, I know, has led most observers to suggest that the power of the grip would be insufficient to penetrate the pelt of an adult platypus. If the spur were rigid like that of a cock, and used in a like manner, all would readily agree to such a possibility. Well, I can assure my readers that when the platypus feels inclined, and is prepared to strike, the position of the spur can be styled as rigid. That is to say, it is propped back to the extreme point of erection, where, when striking, it will tear all before it, or become dislocated in the attempt. But the driving power then brought to bear is not alone in controlling the precise movements of the spur. All the leg muscles concerned in the sudden twisting of an ankle combine to force the weapon home. I am speaking from personal experience with wild specimens in the field--not from pickled carcasses.

(From fresh carcass)

Plate 14]

From experiment and observations made in connection with the actual voluntary administration of poison by an enraged platypus, and also by personally lifting to full-cock the clamped weapon of another fresh carcass, I came to the conclusion that, in the erection of the spur to a given point, say, from half-cock to full, the poison dose is regulated accordingly. For instance, when the spur is fully cocked the fluid will flow until a dew-like drop appears at the orifice near the tip. Here, ready for immediate action, the weapon stands fully charged. Its mission at this stage is first to puncture, with solid tip, the skin of the opposing subject. By so doing, the tip readily tears a way, thus preventing clogging of the orifice until the poison makes contact with at least first blood. The desire of the animal is to strike at a vulnerable spot, and the flow of poison would probably be stemmed temporarily if the spur were embedded deeply; but whether the amount of poison is measured automatically at the cocking of the spur, or whether the platypus is able to control the flow after striking, has not been determined. But the fact must be noted that, when the animal attempts to insert the spur and misjudges the mark, the spur is carried on into the fur of its own leg, and the dose spilt thereon is apparently in greater quantity than that which the tube of the spur could possibly hold with the one filling. Seemingly, then, the well at the base of the heel is drained also with the complete clamping of the spur, having been shut off from the main supply at the initial filling. It seems reasonable to suppose that the spur must be re-cocked before a similar operation can take place, otherwise there would probably be a constant leakage while the spur is clamped normally out of action.

Plate 14]

Apart from the controversy as to whether the poison is deadly or not, I strongly advise the uninitiated not to meddle recklessly with a male platypus, in or out of season, for I am quite convinced that when once the animal grips correctly, especially with both spurs, unless the platypus releases voluntarily (which he is not likely to do readily) the creature would surely have to be killed before the spurs could be extracted. Failing this, there is obviously only one other way out of it, and that is to lance or tear the tortured flesh of the victim.

The sudden twist of the ankles, referred to above, may best be illustrated thus. Clench both fists, place the hands side by side with the fingers uppermost, then open the palms to the extreme, suddenly, and note the rigid position of thumbs. While in that position, regard the palms as the soles of platypus feet, and the extended thumbs as “set-back” spurs. Of course, in the case of the platypus the incurved shape would incline towards the finger-tips, but to follow this curve with the thumbs the rigidity essential for striking purposes would be lost. Very well, let that be understood. At this point, then, imagine an enemy to be lodged in the palms, and held there firmly by clutching talons. This may be represented by clamping the extremities of the fingers tightly, without closing the palms. Then, with a jerk simultaneously twist both wrists inwards to the full, finishing with the backs of the hands uppermost, and thumbs clenched beneath. This will serve to convey some idea as to the awkward position of the victim so secured by an infuriated platypus.

Of an endeavour to test the effect of platypus poison on a freshly-trapped rabbit my report is as follows. Not being fully equipped with the poison collected directly from the spurs of a living specimen, because of its being swabbed up by the fur on the thigh of the animal each time the fluid was ejected through the then clamped spur, I was compelled to extract the secretion from the glands of a freshly-killed specimen. Using a hypodermic syringe, I injected into the thigh muscle (not a vital part) of the rabbit what I considered to be a double dose of the poison, that is to say, as much as the platypus would inject with both spurs simultaneously. I observed the rabbit closely for two hours after, but did not notice any change in its behaviour. My final examination, twenty-four hours later, found the subject very quiet, but otherwise apparently well. On killing the rabbit I found a discoloured swelling of the muscle surrounding the punctured portion, and between the skin and muscle a frothy cream-coloured corruption, quite foreign to the immediate conditions of those parts. This then is slight evidence that, at least, the rabbit suffered pain, but to what extent I could not estimate. Still, if the effect is sudden, as I believe, then it would serve the essential purpose of putting an opponent temporarily out of action at the desired moment, and for a sufficient length of time.

Where the method of striking has been observed and described, observers agree that the hind legs are brought together, causing a wound on both sides of the intervening object, which must be of comparatively small dimensions--a finger, a hand on edge, or the sharp muzzle of a dog. The animals concerned are wounded in several instances and badly frightened in others.

Taking warning from the mistakes of zoologists who have, in the past, argued plausibly about the platypus, only to be proved wrong in the end, one should refrain from argument unless armed with practical experience and observation in the field. My observations of the method of copulation were made without thought as to the function of the spurs, and I think they prove clearly that that function is definitely connected with copulation. This brings us to the fifth suggestion:--

(5). That the spurs are used for holding the female during the sexual embrace. This suggestion was first put forward by Home in 1802. He elaborated it in his Lectures on Comparative Anatomy (1823), in which he writes:--

“When I first saw the spur, I had no doubt from its situation but that one of its purposes was to prevent the escape of the female during the act of the coitus; in this I was confirmed when I found in the female, exactly in the same situation, a regular socket, lined with strong cuticle, adapted to the reception of the spur.... Having ascertained that a secretion is emitted through the spur of the male into this socket, and the parts being so minute as to require glasses of considerable power, I got Mr. Bauer to examine the socket in the female; and after overcoming considerable difficulties, the parts being very much corrugated, and yet retaining their elasticity, he made out the form of this socket, which corresponds exactly in shape to the spur itself: so that, when completely introduced, it must be so grasped that the male would be unable to withdraw it when coitus was over; in this respect resembling the effect of suction. The male, it would appear--at least this is the best conjecture I can make by reasoning from analogy, there being no facts to guide us--by throwing some of the secretion of the gland in the thigh into the socket, dilates it, and releases the spur; the liquor injected being acrimonious, will also irritate the female, and make her use efforts to escape.”

Martin and Tidswell (loc. cit., p. 481) comment on the above as follows:--

“Home’s suggestion, which had the powerful support of Dr. Bennett, cannot be absolutely denied, as no one has, as far as we are aware, ever seen these animals copulating. Home’s main reason for such an hypothesis was that in the female there are situated in corresponding situations slight hairless depressions.

“It seems to us that for the male to apply its spurs to these depressions during copulation in the manner suggested by Home would involve an amount of gymnastic ability of which even an Ornithorhynchus is incapable.

“Moreover, Knox and Owen have shown that these depressions in the female are merely the rudiments of the male spur, and that the young female, indeed, actually possesses a spur which disappears prior to the dawn of sexual life.”

The statement contained in the last paragraph seems capable of an interpretation very different from that of Martin and Tidswell. The young of both sexes have a genital protuberance of similar size; in the male it develops into the intromittent organ and in the female it is found in a reduced condition as the comparatively insignificant clitoris, situated on the margin of an invagination. The history of the spur affords an exact analogy.

Until of late years I was under the impression that female platypus might shed their spurs on attaining maturity, if not before leaving the nest. On that account I was persistently on the look-out for cast-offs among the nesting-material, where furred young were found. Now, however, I have come to the conclusion that the spurs are retained by the females, but that, instead of hardening like those of the male, they soften and collapse within themselves to form the so-called socket or calloused area about the ankles, which corresponds in dimensions with the base of the male spur. This, then, would prevent the spur tip from pricking, accidentally, the ankle of the female.

Plate 15]

Note trail of freshly-ejected venom on background.

Plate 15]

In my description of the method of copulation I think it is shown conclusively that the platypus has the gymnastic ability to grip the female with its spurs. Moreover, in the tail-to-tail position, which I shall describe later as occurring throughout the greater part of the coitus, the only possible grip the animals can have of one another is by means of the spur and foot. That this use is feasible has been shown by an experiment with recently killed animals, used while they were still in a pliable condition.

If we now turn to echidna, as we very well may--for an explanation which is adequate for the platypus must be adequate also for the echidna--what do we find? A gland is present, popliteal rather than femoral in position (which leads Owen to prefer the word “crural” as covering both), but much reduced in size, which is equal to that of a small pea, with a reduced duct running to the spur. I rely on Owen’s account in the Penny Cyclopaedia, confirmed by a recent reinvestigation by Mackenzie and Owen (1919, p. 38), in which the authors conclude:--“In our opinion this body shows evidence of retrogression similar to that seen in the vermiform appendage and other structures.”

No case of venomous wound caused by the spur has been recorded against the echidna. Semon (1894, p. 7) writes as follows:--

“There can be no doubt that the spur of the male, and the glandular apparatus connected with it, is to be looked upon as an organ for sexual excitation. Without at present bringing forward any theory as to the function of the organ, I can at least completely substantiate Bennett’s observation that the significance of the spur is not as a poison weapon, nor, indeed, any kind of weapon at all. Not one of the hundreds of echidnas which I have handled in a living state ever tried to use its spur as a weapon.”

It is generally believed that the echidna has evolved its spiny covering for protective purposes, but it is obvious that spines are useless as offensive weapons. Semon has apparently been influenced by Home’s theory as to the use of the spur for sexual excitation, and by Bennett’s opinion that the spur is not used as a poison weapon. His own experience in handling hundreds of echidnas is not conclusive evidence against the use of the spur as a weapon, for the reason that, when handled, they tuck their legs within the protective covering of their spines. The only way to prevent the echidna from rolling itself into a ball is to place it on its back on a board, with straps at the corners securing all its legs. In that position its spurs are out of action. The animal apparently has no need of an offensive weapon against enemies in general; but in all forms of animal life there is rivalry among the males, and whether the echidna ever used, or still uses, its spurs during copulation, or not, it would appear reasonable that the spur is the natural weapon for males to use on each other, especially as the only way in which they can possibly come together in combat is on their hind legs, using the out-turned claws as supports, and with the front of their bodies in contact for their full length. In this position their spurs could be used on the only vulnerable portion of each other, whereas, if the contest for possession of the female were to be carried on in any other position, the result must be a stalemate owing to the impregnable covering of spines.

Bill Lancaster, of Manilla, N.S.W. (who has been my assistant in field work), informed me that only once in his sixty years of bush experience did he see the echidna in the act of copulating. It occurred on the side of a mountain. He described the participators as forming one large ball of quills with a pair of muzzles just protruding at one end, the whole resembling a spiny melon with split stalk attached. After a minute or two Lancaster rolled them over with his boot and, as this had no effect, he deliberately kicked them down the mountain side, but even this failed to separate them and they remained together for some time after reaching the flat ground below.

I have since examined many echidna specimens (both sexes) and noted particularly the “cowlick” formation of their quills about the hinder parts. These they are obviously unable to close down completely even when walking in freedom in the bush, quite unaware of the presence of an observer. I therefore consider it impossible for these creatures to copulate in any other position than that described by Lancaster--abdomen to abdomen, and head to head. Of course, they may prefer to lie on their sides in the initial stages, but I consider it more feasible for them to stand up on their hind legs, partly supporting each other with their fore-paws until the desired position is attained; after that, any attitude may be assumed; but, for the sake of safety to both during the breakaway, the side-to-side movement should prove the simplest.

On August 11, 1919, I examined the spurs of an adult male echidna, and found them embedded in a swollen fleshy sheath on the external portion of its heels, or lower legs. On pressing the sheath down, the spurs appeared to shoot up suddenly, like a splinter from festered flesh. Here I discovered, around the base of both spurs, a creamy-coloured discharge, which I consider, if applied to an open wound, would not tend to heal the flesh. The condition appeared to be quite normal, but I do not know of any previous record of a similar observation, and cannot offer any opinion as to its purpose, or whether it was peculiar to the mating season.

If it is impossible for the male to make use of his spurs during copulation while in the position described by Lancaster, the grip is evidently obtained by the curiously-shaped long claws of both sexes.

Wood Jones (1923, p. 37) sums up the position in regard to the platypus in the following terms:--

“Thoroughly reliable observations, however, carry us this far. The male Ornithorhynchus can, and at times does, strike with its spurs when handled. The spurs are capable of inflicting a wound, and this wound is followed by definite symptoms. The symptoms are somewhat akin to those present in cases of non-fatal snake-bite, and men and dogs are equally affected when wounded by the spur. So far as I can ascertain, no recorded observations have ever given support to any of the various opinions that the apparatus has functions other than that of an offensive and defensive weapon. That the recorded observations show that the spur is not invariably made use of when the animal is handled, is of little moment.

“We may say, therefore, that the male Monotreme possesses a secreting gland, a duct, and a hollow spur, as an anatomical entity; that the gland undergoes seasonal changes in activity; that its secretion, when injected into animals, is decidedly poisonous, and that its composition, and its effects, are probably akin to those of snake venom; that the symptoms produced by the experimental injection of the secretion into animals are similar to those described in well-authenticated cases of wounding of men, or dogs, by the spur of the living male Platypus.

“Because we have limited ourselves to the statement of certain well-ascertained facts concerning its use as a weapon, it must not be imagined that it is considered impossible that the animal may put the spur to other uses. The Monotremes are not easy animals to observe, and possibly many of their habits remain quite unknown for lack of proper opportunities for observation. But there is little to be gained by mere speculation as to the function of structures found in living animals. Observation of the living creature is required.”

Despite this judicial warning, I must plead guilty to indulgence in speculation. It has, however, been based on observations which were not available to Wood Jones. One concerns the method of copulation; this observation is admittedly incomplete, and it will probably be necessary to take a pair in the act of copulation to settle the matter. The second may now be detailed.

While drying a male platypus upon my knee with a towel, I felt an increasing pressure of the soles of the animal’s feet upon my thigh, and hurriedly raised it, thinking that it might be trying to use its spurs. I then noticed that the spurs had penetrated through a fold in the cloth of my trousers, which was moist from the expressed secretion. On experimenting further with this animal, I noted that there was no attempt to strike with the spurs, as does a cock. The intervening object was first grasped with the hind feet, which were then pressed firmly against it, and the spurs were brought together with a deliberate probing motion, which may be likened to the process of sewing with a packing-needle.

Finally, there is the question of expression of the secretion. Several observers have commented that they were unable to force it out by pressure upon the gland and duct. Martin and Tidswell remark upon the absence of muscular elements in the duct, and wonder how the secretion is kept from wasting. The solution of the matter may be found in Jamison’s observation--“This unexpected and extraordinary occurrence induced me to examine the spur of the animal; and on pressing it down on the leg the fluid squirted through the tube” (1818, pp. 584-5). The animal is, of course, able to bring this about by muscular action, and is not dependent upon pressure against external objects for expression of secretion. Plate 15 shows a photograph of the foot and spur of the male referred to above. In preparation for taking the photograph, a piece of card, in which a slit shaped like a button-hole had been cut, was passed over the foot to serve as a background. In adjusting this card so that the slit should not appear in the photograph, it was revolved about a quarter turn, a process which caused continuous irritation to the muscles above the base of the spur while the point was resting on the card. The result was a trail of secretion which is clearly visible in the illustration.

After weighing all the evidence, and as the result of my own observations, I have therefore come to the conclusion that the uses of the spur of the male platypus are those set out in the fourth and fifth suggestions, namely, as weapons and for holding the female during copulation.

Note excavated burrow commencing at water-level, between figure of collector and oak-tree at right, then winding up the bank to black patch (near tussock grass) where nest was found.

Plate 16]