352 APPENDIX. 



above, with a minute submarginal apex ; inner lip large, flattened 

 or slightly convex, the margin smooth or crenulate ; outer lip 

 usually a little thickened and sometimes crenulate within, and 

 more or less continuous with the inner lip ; aperture compara- 

 tively small ; surface smooth or radiately ribbed ; usually polished. 

 Differs from Dostia in its more nearly perfect bilateral symmetry 

 and minute apex ; from Velates in its marginal apex. 4 sp. 

 Cretaceous and Laramie ; U. S. 



Cyclostrema, Marryat [p. 299]. 



THARSis, Jeffreys, 1883, {Etym. — One of the many synonyms 

 of Cyprus.) Shell globular, solid and glossy; peristome circular 

 and continuous, but attached to the pillar on that side ; base 

 closed by a pad or thick testaceous layer in the adult, perfor- 

 ated in the 3''0ung ; operculum chitinous or horny, and multispiral. 

 This genus differs from Cyclostrema in the peristome being, 

 although continuous, not free or detached from the rest of the 

 shell, and in the umbilicus being closed instead of open in the 

 adult. Type, T. Bomettensis, Seguenza. Mediterranean. 



GANESA, Jeffreys, 1883. {Etym. — The Hindoo god of science.) 

 Shell shaped like a Natica, thin ; peristome continuous^ free and 

 separate in the young, but united to the peripherj^ in the adult; 

 spire having an oblique axis ; base perforated, not umbilicate ; 

 operculum horny, multispiral. Differs from Tharsis in the ob- 

 liquity of the spire and the perforation of the base at every 

 stage of growth. 2 sp. Europe. G. pruinosa, Jeffreys. 



Fissurellidse [p. 326]. 



? DiRiNus, M'Coy, 1844. 

 Distr. — D. Bucklandi, M'Coy. Carboniferous ; Ireland. 

 Patelliform ; apex perforated by two oval foramina, symmet- 

 rically placed one on the right side, the other on the left. 

 A very problematical fossil. 



Cylichna, Loven [p. 359]. 

 CRYPTAXis, Jeffreys, 1883. Shell small, white, glossy, sometimes 

 with fine revolving strife; spire deeply sunken, and for the most 

 part concealed in a small cavity in the centre of the crown, but 

 showing the apex and sometimes one or two whorls at the bottom 

 of the cavity. 4 sp. Deep-sea ; Europe. G. crebripunctatus, 

 Jeffreys. Intermediate between Cylichna and Utriculus. 



Rhodope, Kolliker [p. 391]. 



This is not a mollusk, but a peculiarly aberrant Turbellarian. 

 — Science, i, 433. 



