Notes on South African Mollusca. 115 



thicker, situate a little less than half-way from the base to the apex 

 of the aperture. 



Dimensions of a typical specimen from Tasmania, in the British 

 Museum : Long. 9'2 ; lat. 5-3 ; apert. 6 x 3'6 ; last whorl 8 - 4 mm. 



There is no epidermis, the shell appearing to be a little beach- 

 rolled. 



Hab. TASMANIA. Oyster Cove, near Hobart Town (Milligan) ; 

 near Pirates Bay ; Tasman's Arch (May). 



Antipodes Islands (Bollons). 



Type ubi ? 



Hedley and Suter selected this species as the Type of Swainson's 

 genus Cremnobates, and published a few notes on its anatomy. This 

 does not appear to differ to any considerable extent from that of 

 M. tristanensis, as diagnosed by Robson in these pages, except that 

 in parva "a central tooth could not be distinguished," while in 

 tristanensis a central tooth is shown, but an infinitesimally small 

 one. Without knowledge of the power of magnification employed, 

 it is hardly safe for me to suggest that this feature may possibly 

 exist and have been overlooked in the Tasmanian animal ; but Mr. 

 Robson informs me that it took a ^ Homog. imm. objective to 

 enable him to trace it in tristanensis. 



The shell of parva is certainly that of a true Marinula, and, on 

 the whole, there seems hardly sufficient cause for regarding Cremno- 

 bates as other than synonymous with King's genus, although, on the 

 other hand, Hedley and Suter's description of the anatomy gives us 

 no definite clue for uniting the two genera. 



MARINULA FILHOLI, Hutton. 



1878 Marinula filholi, Hutton, J. de C. xxvi. p. 42. D. 

 1880 ,, ,, ,, Man. N.Z. Moll. p. 34. D. 



1913 ,, ,, Suter, Man. N.Z. Moll. p. 591. D. 



Shell small, prolonged ovate-acuminate, imperforate, pale cor- 

 neous. Spire somewhat produced, nearly as long as aperture, 

 sides convex, apex mamillate. Whorls 3J-, convex, rapidly in- 

 creasing, finely microscopically striate parallel to the lines of 

 growth. Aperture ovate, outer margin thin, simple ; inner bearing 

 three prominent white dental processes ; a long, thin tooth about 

 equidistant between the outer lip and the next process, a smaller, 

 conical tooth, which is situate a little more than half-way down from 

 the apex of the aperture to the base ; below the second, and parallel 

 to it, is a still smaller tooth or fold, half the size of the central one. 



10 



