PLEUROTOMA. MOLLUSCA. 41 



plicated, yellowish red ; the plaits distant, black, transversely 

 sulcated with white ; whorls angular in the middle ; three or four 

 plaits on the columella. 2J inches long. Lister, pi. 922, fig. 15. 



Gen. 85. PLEUROTOMA, Lam. Murex, Lin. 

 Shell turreted or fusiform, terminated below by a straight canal, 

 more or less long ; outer lip with a fissure or notch at the 

 upper part. 



This group was included in the genus Murex by Linnaeus, and in the genus Fu- 

 sus by Bruguieres. It differs, however, from both, in wanting the ridges by which 

 the Murices are distinguished, and in having a fissure or notch at the outer lip. M. 

 Lamarck had divided the group into two genera, which he termed Clavatula and 

 Pleurotoma, distinguished by their having a short or elongated canal ; but, finding 

 that in this respect they run into each other insensibly, finally retained them all 

 under the present generic term. 



P. Babylonia, Lam. Shell turreted, fusiform, transversely carinated 

 and banded ; white, with the bands spotted with black ; whorls 

 convex ; beak long and straight. 3 inches long. Inhabits In- 

 dian Ocean. Lister, pi. 917> % 11- 



P. nodifera, Lam. Shell fusiform, turreted, reddish yellow, the 

 middle of the whorls angulated ; above the angle smooth, below 

 transversely sulcated, the angles tuberculated ; beak shorter than 

 the spire. 2 inches long. Lam. vii. 96. 

 The fossil species belonging to this genus are numerous. On the Continent they 



have been found at Grignon, and in the neighbourhood of Bourdeaux. 



Gen. 36. CERITHIUM, Brug. Murex, Strombus, Lin. 

 Shell turreted ; aperture oblong, oblique, terminated at the base 

 by a short canal, truncated or recurved, never notched ; a 

 gutter or furrow at the upper extremity of the outer lip ; 

 operculum small, orbicular and horny. 



The spire in this genus forms at least two-thirds of the length of the shell. Its 

 form is an elongated cone or pyramid, the surface of which is rarely smooth, but al- 

 most always crowded with striae, granulations, tubercles, or spines, and sometimes 

 varices. This genus^is numerous in species, and are all inhabitants of the sea or 

 salt marshes at the mouths of rivers. The animal inhabitant crawls by means of a 

 small and suborbicular disc, which is termed t the foot. The head is truncated below ; 

 bordered with a crest or fringed ridge, and furnished with two pointed tentacula, 

 with the eyes on a projection at their base. 



C. telescopium, Lam. Shell conical, turreted, transversely sulcated ; 



columella with a single plait ; canal very short ; margin recurved. 



Inhabits Indian seas. Bonan. 3, fig. 92. 



This shell is three or four inches long, of a brown or blackish colour, generally 

 marked with a paler band round the margin of the body whorl. The base is nearly 

 flat, and the pillar protuberant. 



C. obeliscus, Lam. Shell turreted, transversely striated, yellow, with 

 red and fuscous points ; whorls with three granulated ribs, and 

 the suture tuberculated ; columella with one tooth and the beak 

 ascending. 2 inches long. Inhabits coasts ef Jamaica and Bar- 

 badoes. D'Argenv. pi. 11, fig. F. 



C. aluco, Lam. Shell white, spotted with black, with a trans- 

 verse tuberculated line on the lower whorls, and the upper ones 



