214 



Tbigonia acuticostata. 

 This, the earliest discovered of the Tertiary species of the 

 genus, was described by McCoy from specimens obtained 

 from the Muddy Creek beds in Victoria, probably on the 

 same geological horizon as those at Table Cape in which it 

 has not yet been found. It has, however, in latter years, 

 been reported by McCoy as living on the south-eastern coast 

 of Australia, and it also occurs in Newer Tertiary strata 

 at Mordialloc ; Hobson's Bay ; Eiver Murray Cliffs, at the 

 Nor'-West Bend ; and at Aldinga Bay, St. Vincent's Gulf. 



Rhynchonella squamosa. 



This palliobranch, common to the Older Tertiary of South 

 Australia, Victoria, Tasmania and New Zealand, must now 

 be catalogued among recent species, as I have no doubt that 

 U. nigricans, var, pixydata, Davidson, in " Brachiopoda of the 

 Challenger Expedition, t. 4, f. 14, p. 59, 1880," is its living 

 representative. 



The differential characters of the so-called variety pixydata 

 are the more numerous scaly ribs (40 to 46), and the less 

 transverse and comparatively more convex shell, characters 

 upon which Hutton founded the species B. squamosa As 

 the differences are not mere individual variations, they must 

 be regarded as of specific value, so largely supported by the 

 facts of the present and past distribution of the two species. 



U. squamosa, as an existing species, is known only in deep 

 water off south of Kerguelen Island, and as a fossil in the 

 Older Tertiary of South Australia, Victoria, Tasmania and 

 New Zealand. B. 7iigricans extends in time from the oldest 

 Tertiary formation to the recent epoch in New Zealand, and 

 has not been found in association with B. squamosa, except 

 in the Oamaru formation in New Zealand. 



ON THE COMMUNITY OF SPECIES OF AQUATIC 

 PULMONATE SNAILS BETWEEN AUSTRALIA 

 AND TASMAINIA. 



By Professor Ralph Tate, F.E.S.jF.L.S., Core. Memb., Etc. 



[Bead June 9, 1884.] 

 LiMNAEA HuoNENSis (Tenisou-Woods) . 

 Tenison- Woods, in his paper on the freshwater shells of 

 Tasmania (Proc. Roy. Soc, Tasmania, for 1875), describes 

 four species of the ^enu^ Limnaea ; but, subsequently (loc. 

 cit., 1878, p. 72), he writes that "I/. Hohartensis of my mono- 

 graph, I find, on comparison, to be quite undistinguishable 



