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ON THE FRESHWATER SHELLS OF TASMANIA. 



By Eev. J. E. Tennison Wools, F.G.S., F.L.S. 

 [Bead dth August, 1875.] 



Introduction. — No attempt lias yet been made to arrange 

 the freshwater shells of Tasmania. The land shells have 

 been • carefully catalogued by Mr. Legrand, so that little 

 remains to be desired in that department of our island, fauna. 

 The marine shells have received much attention from most 

 eminent naturaUsts, though a list carefully criticised, with a 

 well arranged account of the bibliography is much wanted. 

 But the freshwater shells have been almost entirely neglected. 

 There have been one or two descriptions of Physa in Reeve, 

 and one or two other notices of species scattered through 

 various scientific publications, but the majority of the shells 

 here described are new to science. This comparative neglect 

 has one advantage, which is, that the whole can be done 

 without a troublesome synonomy. There are other advantages 

 in describing species in their native country. Mistakes as to 

 the habitat are thus avoided by the examination of la,rge 

 collections, all the variations to which any species is subject 

 can be observed, and details which in isolated specimens 

 might be regarded as of specific value are rightly estimated, 

 and the unnecessary multiplication of species obviated. For 

 this reason I am sure that it is no real gain to science to 

 send one or two natural history specimens to scientific men 

 at home no matter how eminent they may be. In this way, 

 a hopeless confusion of names and habitats arises, no accurate 

 knowledge is gained, and science is, in fact, really retarded. 

 I say this because in the very subject I am now writing upon, 

 I find in various eminent scientific woi'ks descriptions of Aus- 

 tralian freshwater shells, which I have very little doubt were 

 derived from Tasmania ; and, further, I also find shells 

 described as Tasmanian, which the most careful and pains- 

 taking collectors assure me have never been found in this 

 island. Such instances I will note as I proceed. 



The first fact that strikes us in the examination of the fresh- 

 water fauna of Tasmania is its perfect distinctness fi'om tha.t 

 of Australia. The latter is well marked, and there is the 

 greatest distinctness between shells gathered in different parts 

 of the continent. But with this fact there is another still 

 more remarkable, that one of the Tasmanian Physse, and that 

 the most common seems scarcely to be distinguished from the 

 common Physa fontinal is of Europe, and it is found in places 

 which preclude the supposition of its having been introduced. 

 Moreover the fades or general character of our freshwater 



