66 A REVISED CENSUS OF THE TASMANIAN FLUVIATILE MOLLUSCA, 



British Museum, from which it can be easily identified. 

 Tenison-Woods was the first to work at these forms on 

 the spot, and had a large amount of material placed 

 in his hands by Leg-rand. Considering this naturalist's 

 reputation, and opportunities, it is extraordinary how 

 little value can be set on his work. Of 24 species of 

 fluviatile shells described, only about six can be main- 

 tained as distinct species, but he must receive credit 

 for partly admitting his errors, for when dealing with 

 Bythintlla nigra in these proceedings for 1879, pp. 71- 

 72, he unites with it four of his supposed species. Of his 

 four species of Lymna?a, /-. tasmanica is admitted by him- 

 self, Proc. Roy. Soc, Tas., 1878, p. 72, to be founded on 

 the introduced L. peregra, and the three others are pro- 

 bably variants of one native species (see Petterd, Journ. 

 Conch, ii., p. 81). His six species of Physa all become 

 sunk in synonymy. Fortunately a type series of these was 

 mounted and placed in the Tasmanian Museum, Hobart. 

 Many of these are broken, and some quite destroyed; of 

 the four species and two varieties that remain I have 

 prepared figures for this paper. Of P. tasmanica, one per- 

 fect specimen remains on the card, it seems conspecific 

 with P. pyramidata Sowerby ; var. a., the single specimen 

 seems scarcely adult, it appears to equal P. gibbosa Gould; 

 var. b. . of hve specimens mounted, one is the same as 

 var. a. ; nrobably the others are the same also, but in 

 a more adult state, P '. ciliata, four specimens, some 

 rather broken ; two are short spired, and practically iden- 

 tical with the last; two are long spired, resembling the 

 next, P. legrandi, one large specimen, thin, and probably 

 not quite adult, probably is a rather stout form of P. 

 pyr&midata. P. fouonensis, four specimens have been 

 mounted, but all are destroyed ; Petterd, who probably 

 saw the types, considered it equalled tasmanica. 

 P. huonicola — no trace of this species seen, but the de- 

 scription would seem to bring it under pyramidata. P. 

 tasmanicola, eight specimens have been originally mount- 

 ed, of which one remains perfect, (Another specimen 

 remaining is Potamopyrgus tasmanica). I consider this 

 species undoubtedly a juvenile of pyramidata. 



Our author was not more fortunate in dealing with 

 the small Amnicola-like species in our streams. Three 

 of his species are synonyms of P. nigra, and it is difficult 

 to see with respect to two of them, viz., B. legrandi. and 

 tasmmiica, how he could see any difference from nigra, 

 or from one another. The same remarks apply to two 

 ether species, which become united to P. gunnii. Type 

 scries of these were also presented to the Museum, and 



