PART II. CEBITHIN-ffi. 315 



SuB-rAM. 5. CERITHIN,. 



Shell clavate, generally mucronate ; the spire very long ; 

 the outer lip considerably dilated ; the base either trun- 

 cate, or forming a short recurved channel. 



POTOMIS Brong. Fluviatile ? covered with a brown 

 epidermis : whorls coronated, and armed with spines ; 

 aperture almost entire, the notch being slightly de- 

 veloped ; top of the outer lip with an obsolete sinus, 

 muricata. Sow. Man. 377.* granulata. En. M. 442. f.4. 



PIRENA Lam. Fluviatile ; smooth ; outer lip 

 much dilated, with a deep narrow slit on the 

 upper part; base widely notched; inner lip 

 entire and thickened, t 

 P. terebralis. Sow. Man. f. 316. (fig. 80.) 



*TEREBRALIA Sw. Outer lip much dilated, 

 generally uniting at its base to the inner 

 lip, leaving a round perforation at the base 

 of the pillar ; channel truncate ; operculum 

 round. 



palustre. Mart. f. 1472. heteroclites. Lam. No. 24. 



sulcatum. En. M.442. f. 2. telescopium. Voy. Ast. pi. 55. 

 Ebenium. Ib. 442. f. 1. f. 46. 



RHINOCLAVIS Sw. Channel curved backwards in an 

 erect position ; inner lip very thick, with a tumid 

 margin ; pillar generally with a central plait ; oper- 

 culum ear- shaped. 



lineatum. En. M. 443. f. 3. obeliscus. En. Meth.^S.f. 4. 



vertagus. Ib. f. 2. aluco. Ib. f. 5. (Aberrant.) 



subulatum. Lam. No. 23. semi-granosum. Ib. 443.f. 1. 



fasciatum. Mart. 157. f. 1481. asperum. Mart. 157. f. 1483. 



CERITHIUM Lam. Channel short, nearly straight ; pillar 

 smooth ; inner lip thickened only at the top, where 



* Connecting this with the last sub-family by means of Clavicantha. 

 t Representing Pleurotoma. 



