116 Proceedings of the Royal Society of Victoria. 



70. Thylacodes pudis, Tate. 

 T. rudis, Tate, Gast. IV., 1893, p. 343, pi. ix., fig. 8. 



71. Tenagodes occlusus, T. Woods. 

 Tenagodus occhisus, T. Woods, P.R.S.Tas., 1876, p. 100. 



72. Potamides pyramidale, Tate. 

 Id., Tate, P.R.S.Tas., 1881, p. 226. 



73. Potamides semicostatum, Tate. 

 Id., Tate, P.R.S.Tas., 1884, p. 226. 



74. Rissoa dubia, Johnston. 



Id., Johnston, P.R.S.Tas., 1879, p. 33. 



Obse7-vations. — Owing to the very brief description of this 

 species it is a somewhat ditiicult matter to come to an absolutely 

 definite conclusion ; but the present specimen, after careful ex- 

 amination, I am unable to distinguish as distinct from Mr. 

 Johnston's description, except that it is twice as large as the 

 specimen of which he gives tlie dimensions. 



75. Astralium flindersi, T. Woods. 

 A. {Cix\ciiv)fliiidersi, T. Woods, P.R.S.Tas., 1876, p. 95. ■ 



76. Astralium ornatissimum, T. Woods. 

 A. (Calcar) ornatissimum, T. Woods, P.R.S.Tas., 1876, p. 96. 



77. Astralium (Imperator) johnstoni, sp. nov. 



Imperator {P<LsXxi\\\\x\\\) imperiak2 R. M. Johnston, P.R.S.Tas., 

 1876, p. 90r. 



Imperator hudsoniana, R. M. Johnston, Geo. Tas., 1888, pi. 

 xxix., tigs. 12, 12<7. 



Imperator tasmanica, R. INI. Johnston, MS., op. cit., p. 239. 



Description. — Shell large, depressed trochiform, somewhat thick, 

 consisting of a few flatly convex wliurls, which are spirally ornate 

 and strongly keeled, the keel bearing strong erect and forwai'dly 

 projecting scales, and with a very deep umbilicus. Embryo 



