Part 39

Habitat: New Zealand.

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PLOTUS NANUS NEWT. & GAD.

Plotus nanus Newton and Gadow, Trans. Zool. Soc. XIII p. 288, pl. XXXIV figs 1-5. (1893).

The humerus, the pelvis with sacrum, and the tibia were the materials on which our authors founded this new species. They state that all the strongly developed characters in these bones leave no possible doubt as to its being a species of Plotus, and its diminutive size at once distinguishes it from the three known species--P. anhinga, P. melanogaster, and P. novaehollandiae.

The measurements are as follows:--

Left humerus, length 89 mm. Left tibia, length 61 "

Distance from acetabular axis to anterior end of sacrum 30 mm.

Distance between ventral inner margins of the acetabula 14.5 mm.

Habitat: Mauritius. (Also recorded from Madagascar.)

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"CHENOPIS SUMNERENSIS" FORBES.

Chenopis sumnerensis Forbes, Trans. N.Z. Inst. XXIV, p. 188 (1892) (Nomen nudum).

This appears to have been a very large species, with not very great powers of flight, if not flightless.

Habitat: New Zealand and Chatham Islands.

Bones from Chatham Islands in my collection.

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CHENALOPEX SIRABENSIS ANDREWS.

Chenalopex sirabensis Andrews, Ibis 1897, p. 355, pl. IX, figs. 1-3.

This species of which skull, sternum, pelvis, the bones of fore and hind limbs, &c., are preserved, appears to be closely allied to Chenalopex aegyptiacus, but has such a number of small differences that Mr. Andrews is, I think, quite justified in separating it; I do not, however, agree with him when he suggests that perhaps it is the same as Newton and Gadow's Sarcidiornis mauritianus, although many of the bones agree. Of course, his line of comparison was strengthened by the fact of subfossil bones of Plotus nanus occurring both in Mauritius and Madagascar; but it does not follow that because in one family of birds the same species occurred in two places the others must do likewise, and, therefore, one must not necessarily regard a certain similarity of osteological characters as proof of identity. I must here again refer my readers to Mr. Andrews' very full description.

Habitat: Sirabé in C. Madagascar.

The measurements are:--

Coracoid 67-75 mm. Humerus 132-147 " Radius 126-134 " Ulna 129-142 " Metacarpus 76-85 "

The smaller bones, undoubtedly, belonged to female, and the larger to male individuals.

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CENTRORNIS ANDREWS.

Allied to Chenalopex and Chenopis, but differs from Chenalopex in the form and proportion of its metatarsus, and from all other Anserine forms by the extreme length and slenderness of the shaft of the tibio-tarsus and the relative shortness of the fibular crest. From Chenopis it differs in several respects, and the very long fibular crest of the latter at once separates them.

CENTRORNIS MAJORI ANDREWS.