94 DR. GWYN JEFFREYS ON THE MOLLUSCA OF THE [Mar. 6, 



Distribution. Str. Messiua (Granata-Orillo), Palermo (Montero- 

 sato), Tunisian coast (' Shearwater ' Exp.), Bay of Biscay (' Travail- 

 leur' Exp. 1880), G. Marseilles ('Travailleur ' Exp. 1881) ; 108- 

 1093 fms. 



Fossil. Pliocene : Calabria and Sicily (Seguenza). 



Genus Gane'sa ', Jeffreys. 



Shell shaped like a Natica, thin : peristome continuous, free 

 and separate in the young, but united to the periphery in the adult : 

 spire having an oblique axis : base perforated, not umbilicate : ojjer- 

 culum horny, multispiral. 



Differs from Tharsis in the obliquity of the spire and perforation 

 of the base at every stage of growth. 



ty 1. Ganesa pruinosa^ Jeffreys. (Plate XIX. fig. 8.) 



Shell nearly spherical, of a delicate texture, semitransparent, 

 lustreless and having a remarkably frosted appearance : sculpture 

 very peculiar, and consisting of minute and numerous, but irregu- 

 larly disposed, white tubercles, which are partly embedded in the 

 substance of the shell ; one specimen is marked by slight spiral 

 lines below the suture of each whorl : colour dull white : spire 

 raised : lohorls 4, swollen ; the last exceeds in size three fourths of 

 the whole shell ; apex prominent and twisted : suture deep : mouth 

 nearly circular, angulated at the upper corner : base oblique, having 

 a small and narrow umbilical chink : operculum glossy, having the 

 edges of the whorls raised. L. 0*1 75, B. 0'15. 



'Porcupine' Exp. 1869: St. 23. 1870: Atl. 17, 17a. A few 

 specimens. 



ly 2. Ganesa nitidiuscula^ Jeffreys. (Plate XIX. fig. 9.) 



Shell differs from G. pruinosa in being exactly globular, opaque, 

 and rather glossy ; the sculpture consists of flexuous but slight and 

 remote raised striae in the line of growth ; the last or body-whorl 

 is not so disproportionately large ; the apex of the spire is depressed ; 

 the mouth is angulated both above and below ; and the umbilical 

 chink is channelled. L. 0*125, B. 0"125. 



' Porcupine ' Exp. 1869: St. 23«. 1870: Atl. 17. 



Distribution. Between the Hebrides and Faroes (' Triton ' cruise) ; 

 570 fms. Very rare. 



Genus Circulus *, Jeffreys. 



Animal not known. 



Shell coin-shaped or forming a circular compressed disk, slightly 

 nacreous or pearly : mouth quadrangular, with a discontinuous peri- 

 stome : umbilicus very wide: operculmn multispiral, as in other 

 genera of Trochidce. 



Originally proposed by me as a section of Trochus, but since 

 adopted by Monterosato as a goieric name. 



^ The Hindoo god of science. ^ fiVosted. 



^ Somewhat shining. * A little circle. 



