CONCHOLOGY. 139 



C nodulosum. C. obtusum. 



C. vulgalum. C. semigranosum. 



C. obeliscus. C. asperum. 



C. granulatum. C. linealum. 



C. aluco. C. vertagus. 



C. echinatum. C. fascialum. 



C. subulatum. C. ocellatum. 



C. heteroclites. C. literatum. 



C. zonale. C. atratum. 

 C. semiferrugineum. C. eburneum. 



C. torulosum. C. punctatum. 



C. tuberculatum. C. lima. 



C. morus. C. perversum. 



C. vertagus. The curved beak Cerithium. PI. 24, fig. 3. 

 Species with evidently a small canal, very short, and re- 

 curved obliquely towards the back. 



C. aluco. The caterpillar Cerithium. 



Species with a canal much smaller, but entirely straight, 

 and a sinus well formed at the posterior union of the two 

 edges. 



C. semigranosum. The semigranulated Cerithium. 



Fusiform, turreted ; apex acute ; the suture with double 

 spiral rows of large granules ; minutely striated transversely, 

 with sulcated granulations ; colour reddish brown. 



2. Pleurotoma. Twenty-three species. 



Distinguished from the Cerithium by having a notch or 

 slit in the right margin. 



Shell fusiform, rather rugged, spire turreted ; aperture 

 ovate, small, terminated by a canal variable in length ; the 

 right edge sharp, more or less notched ; operculum horny. 



Pleurotoma imperialis. Pleurotoma fasciahs. 



P. auriculifera. P. bimarginata. 



P. muricata. P. buccinoides. 



F, echinata. P. cingulifera. 



