< I : i I i 1 1 1 1 i . i . 1 P. > 



aiu EXELISSA, Piette, i 



Shell >mall, elongated, suhrylindriral, soim-wliat piipitnrin. many 



whorled, longitudinally curtate, fcuberculate, or -pin<>-e. hi-t \\horl 



tending tO Separate from tin- axi>, contracted at tin- ha>-: aperture 

 orbicular, entire, the lip produced and ,-liglitly t hiekened, n.lu- 

 mella solid. A7//w/m, Lycett, l*r,:;, i~ a >ynonym. 



I']. KOKMOSA, Lyct-tt i Sfri/rt. ,in,l N//.V/. Cnnrli., t. (I!!, f. (i'J |. 



A (loul)ttiil member of the famil, 



? Genus ITKKOSTOMA, Dohavo. 1S61. 



Shell snuill, turrctcd, suhcylindricjil, \vhnrl> ininicfous, with lon- 

 ^imdinal tubercular ri!s, ami spiral stria 1 ; aperture circular, entire, 

 maririn <lilated, exteriorly thiekem-d. 



P. TUBA, Desh. (Struct. <n/<l X//x/. (.'ouch., t. 72, f. 4'2j. Eocene, 

 Paris basin. 



Genus CERITHIOPSIS, Forbes and Hanley, 1853. 



Small, imperforate, more or less cylindrical, narrow, tuberculate, 

 not varicose; whorls numerous, the last narrower in proportion; 

 aperture small, with a short, truncate, nearly straight canal. Oper- 

 culuni suboval, paucispiral, with sublaterul, internal nucleus. 

 Animal with a narrow foot, subtruncated in front and attenuated 

 behind, with a longitudinal sulcus on the sole; tentacles cylindrical, 

 the eyes sessile at their base ; opercular lobe simple, well developed. 



Radula with an oval central tooth, its margin dentate, a large, 

 bicuspid lateral tooth, and unicuspid laterals with >mooth margin. 

 Mostly occurring in northern and temperate seas. Fossil. Civ- 

 taceous. 



C. TUBERCULARIS, Moilt. 



Section METAXIA, Monts., 1884. 



Base truncate, basal area not cingulate and concave, canal open, 

 incipient. C. RUGULOSA, Sowb. 



Section SEILA, A. Ad., 1861. 



Shell with simple spiral ribs. C. DEXTROVi K- A. Ad. and Reeve. 



i, Monts., is a synonym. 



LOVENELLA, O. Saix. 1878. 



Shell subulate; whorls numerous, cancellated, aperture termi- 

 nating in a short, distinct, reflected canal. ( '. MKITI.A, Loveu. 

 Xortln i- a Nrfx. 



Cerithit'//n, Verrill, 188*2, is a synonym. 



