BY W. F. PETTERD. 65 



Gundlachia has been discovered by Professor Tate in a 

 small stream near Adelaide, South Australia. 



The following genera having representatives in Australia 

 are not known here, viz., Neritina, Melania, Corhicnla, 

 Segmentina and Vivipara, the first two are more characteristic of 

 tropical than temjierate climates. Some few of our 

 aquatic mollusca have a resemblance to those of New Zealand, 

 notably the Unio,th.e species oi Fotamopyrgns, and one of the 

 Lymno'a,i\iQ L.avqmlla ir?(f/o?i, very closely ajiproaches a small 

 species that I have named L. Giinnii. The wide difference in 

 the fluviatile and terrestrial — only about nine species of our 

 land shells extend in range to the mainland — moUuscan fauna 

 of the island from that of Australia, proves that they have 

 been separated for a considerable geological time, although, 

 no doubt, the severance occurred during the earlier tertiary 

 period. 



It will be found that the fresh-water shells of Tasmania 

 present a peculiar series of forms that are well worthy of 

 careful study; and no doubt as the examination of the streams 

 in the more remote portion of the island is undertaken, many 

 additional species will be brought to light and the range 

 of many found to be moi'e extended than is at present known. 



Amphipeplea La.uncestonensis. Tejiison-Woods. 



Plate n. Fig. 11. 



Limnoea Latmcesioncnsis. T. Woods, Pro. Ruval Soc. Tas., 

 1876. 



Limnoea Htionensis. T. Woods, op. cit. 



Hahitat — River Huon, Hamilton, River Ouse (Dyer), River 

 Glenelg, South Australia (Tate), many places about 

 Launceston, St. Leonard's, Carrick, Deloraiue, Circular Head, 

 Rivers Mersey, Forth, Leven and Piper, Flinders' Island, 

 King's Island, Cape Barren Island. 



A careful examination of the types of the two species 

 erected by the Rev. Tension-Woods, preserved in the Hobart 

 Museum, and a comjiarison with many hundreds of examples 

 collected at numerous localities, in all stages of growth fully 

 prove that they are but specimens in different stages of develop- 

 ment. Itisgenerally tobefoundcrawlinguu the marginsandtho 

 bottoms of quiet secluded pools, and is not often met with iu 

 running streams. 



It is very different to the introduced Limnn'a prrrgra of 

 Europe (Plate III. Fig. 13), which I have not met with in the 

 northern portion of the island. 



