Section Vi.--Mollusca.

Of the mollusca inhabiting the shores of the island many are highly interesting, and several are very beautiful. The rare Cypraea umbilicata (Sowerby) inhabits Bass' Strait, as also Trigonia margaritacea (Lam.), Valuta papillaris (Swainson), Venus lamellata (Lam.), Crassatella kingicola (Lam.), solenimya Australis (Lam.), a species of Terebratula, and many others most interesting to the conchologist, and not less so to the geologist, as some forms are now found living abundantly in the Australian seas which are only known in the old world as occurring in a fossil state.

Our Argonaut, or paper nautilus (A. tuberculosa, Lam.), is quite distinct from the European species, and scarcely less beautiful. It is occasionally washed ashore in considerable numbers on the islands in Bass' Strait. The beautiful Janthina fragilis has been washed ashore with its inhabitant on the east coast.

Although many forms are almost purely Australian, there are, nevertheless, a great number of European types, such as species of Mytilus, Venus, Pecten, Ostrea, Patella, &c.

The only kind of shell-fish commonly consumed as an article of food and brought to market is a species of oyster. With the aborigines, however, shell-fish formed a very considerable and important article of diet. La Billardiere describes their diving for Haliotis at Recherche Bay; and abundant remains of their feasts still exist all along the coasts, and, in some places, many miles inland, the shell-fish having been carried in baskets by the women, to situations where fresh water was to be found. The sites of these aboriginal feasts are usually easily to be distinguished from raised beaches, or those accumulations of shells caused by change in the relative levels of sea and land. They may be known by their isolated character and position; by their forming, in many instances, round mound-like heaps, or tumuli; by the shells being injured by fire, often broken into small pieces, intermixed with fragments of charcoal; and from the fact of no small species of shell, not likely to form an article of food, being found intermixed. The species of shell-fish consumed by the aborigines were numerous, and varied according to the locality in which each shell abounded. Those commonly used were the two species of Haliotis, Mussels, a Turbo, and Oyster: several of the smaller bivalves and univalves were, however, occasionally used, but it does not appear that the aborigines of Tasmania ever eat the Unio, so far as can now be traced; in this instance exhibiting a remarkable difference from those of New Holland, with whom the Unio forms an important article of diet.

The land shells are inconsiderable in number, not amounting to more than about six species. The freshwater kinds, including those inhabiting ditches, ponds, &c., are more numerous; but, except the unio, all are small and insignificant. Some species occur abundantly in situations which are perfectly dry for at least six months of the year, and seem, like many snails, to have the power of sustaining life for a long period in a dormant state.