Notes on South African Mollusca. 109 



lip thin, simple, inner furnished with three white dental processes 

 (i) a prominent, linguiform tooth parallel to, and about 1-7 mm. 

 from the outer lip ; (ii) a short, rather conical tooth about half-way 

 between the upper one and the base ; (iii) a minute columellar fold 

 rather nearer the second tooth than the base. 



Long. 10-4 ; lat. 5'5 ; apert. 6'7x4'7 ; last whorl 9'G mm. 



x-2 



MAKINULA TRISTANENSIS, sp. nov. 

 Epidermis purple-black ; lines of growth eroded white. 



Mr. G. C. Robson has very kindly examined the anatomy, on 

 which I am therefore enabled to present the subjoined report : 



On the Anatomy of Marinula tristanensis. By G. C. EOBSON, B.A. 

 (Published by permission of the Trustees of the British Museum.) 



It was hoped that the ample material representative of this species, 

 received for examination from Dr. Peringuey, would have afforded 

 an excellent opportunity forgiving a complete account of the anatomy 

 of this interesting form, the generic position of which is now treated 

 for the first time from the anatomical standpoint. It is to be 

 regretted, however, that the specimens obtained were in such a state 

 of contraction as to render dissection of anything more than the 

 gross anatomy an impossibility. It was possible to make out 

 a certain amount by sections stained with Haematoxylin and 

 Methylene Blue, but the time available for continuing this 

 method not being forthcoming the author is compelled to publish 

 only such descriptions as may serve to indicate approximately the 

 systematic position of the genus, together with a few other notes. 



The radida (Fig. 1) differs in many well-marked characters from 

 those of the genera usually regarded as closely akin to Marinula. 

 There are in each row numerous teeth about 230 the general 

 form and disposition of which readily place it among the Auric ididae. 

 The lateral teeth present a simple rounded main cusp with a slightly 

 hollowed interior edge. The basal plate is produced very far beyond 



