liave been discovered, viz., Helix Tasmaniensis, Gr. B. Sowerby, 

 and Bulimus Gunnii, Gr. B. Sowerby. By tlie kindness ^ of 

 Messrs. Legrand and Eoblin I have been permitted to examine 

 tbeir respective collections, and have succeeded in determining 

 two new species, viz., H. Kuxleyana, mihi, and H. Geilston- 

 ensis, ibid. I bave also been able, from various specimens, to 

 identify another shell as a variety of the existing well-known 

 Tasmanian species, H. Sinclairi. 



This latter form appears to be the only representative 

 of existing species, although there are characteristics of H. 

 Tasmanensis, which relate it to that group of existing shells 

 of which H. Stejphensi may be taken as the type. 



To enable other workers to know readily the features of 

 our lacustrine deposits I have prepared a table of the distri- 

 bution of the flora and fauna of the fluviatile and lacustrine 

 deposits of Australia and Tasmania of tertiary age. The 

 post tertiary deposits are not included. 



I also append descriptions of the following species, viz. : — 



Helix Tasmaniensis, G. A. Sowerby (amended.) 



Helix Huxleyana, n.s., mihi. 



Helix Geilstonensis, n.s., mihi. 



Helix Sinclairi, var. Cox (still existing.) 



A species of Unio, occurring abundantly in the Launceston 

 Tertiary Basin, is now being described by Mr. Eobert 

 Etheridge, jun., JP.G.S. 



As, out of the six shells only one is represented among the 

 living species, the percentage of existing, as compared with 

 extinct forms, is about 17 per cent. 



Of course a percentage from such a small number taken 

 by itself, is of doubtful value, but as it supports conclusions 

 drawn from the remarkably rich fossil flora it is of the 

 greatest importance to those who may wish to study the 

 matter. 

 Helix Tasmaniensis, Gr. B. Sowerby. 



As the description given by Mr. Morris, p. 298, Strzelecki's 

 N.S.W. and V.D.L., is somewhat defective, having been taken 

 from an imperfect cast. I submit the following amended 

 description : — 



Shell thin, globosely conical, umbilicated ; whorls 4^, 

 rapidly increasing, ornamented with fine obliquely- arcuate 

 striae, "crossed by fine spiral lines as in the H Stejpliensi group, 

 flatly convex above, convex below, last whorl tumid, and 

 slightly descending in front; suture somewhat impressed, 

 spire depressly conical ; umbilicus deep, narrow, scarcely one- 

 sixth of the diameter; aperture oblique, ovately lunate, 

 peristome simple ; margins slightly approximating basal 

 margin, slightly dilated and reflexed. Gi-reatest dia., 80 mil. ; 

 least, 25 mil. ; height, 20 mil. ; dia. of umbilicus, 4 mil. 



