•211 



Pleurotoma — continued. 



nodulosa, . ovato-fusifomi ; spire pyramidal, with nine rows of 



short nodulous ribs. . f inch. 

 ventricosa. . ovato-fusiform, ventricose and caudated. . ^ inch. 

 terehralis. . fusiform, with transverse granulated strise and 



dentated keels. . | inch. 

 granulata. . subturreted, granulated, base short. . ^ inch. 

 injiexa. . subturreted ; spire long, plaits separate in their middle, 



a granulated keel. . small. 

 turrella. . subturreted ; the whirls carinated ; spire tubercu- 



lated in the upper part. . small. 

 sfriarella. . fusiform, turreted, almost smooth, plaits and strise 



hardly discoverable. . small. 

 decussafa. . fusiform, turreted; spire small, long, and nodulous, 



wnth two rows of tubercles, one small the other large. . 



f inch. 



Cerithium. 



interruptum. . pyramidal ; transverse strise in rows, alternately 



large and small ; ribs bowed, last turn ventricose. . If 



inch. 

 hexagonum. . with five or six longitudinal ribs ; last whirl tumid, 



with five or six spinous tubercles. . 2 inches. 

 serra^«w. . turreted, echinated ; tv^-o rows of compressed teeth 



on each turn, the lower smallest ; four internal plaits on 



right side. . 2f inches. 

 tricarinatus. . pyramidate ; three denticulated keels, the lowest 



by much the largest — 2 inches. 

 vittatum. . turreted ; upper whirls smooth, lower ones with 



three tuberculated bands — 2 inches. 

 clavatulatum. . rough, with transverse tubercular keels, three 



at the upper part, and decreasing to one on the lowest 



turn ; notched like a. pleurotoma — 1 j inch. 

 echinoides. . rather heptagonal, with tubercles a little pointed, 



in two or three rows ; twelve or fourteen turns, sometimes 



orange coloured — 1^ inch. 

 angulosum. . pyramidate, twelve turns, with transverse striae, 



and a central angulated keel, points at the angles — •!§ 



inch, 

 cristafum. . turreted ; whirls ■^"ith a dentated keel in the middle ; 



the base transversely sulcated — Ij inch. 

 calcifrapoides. . tarreted, with transverse mui'icated ribs, no 



striae — Ij inch. 

 denticulatum. . spire subulated and smooth at the top, the other 



whirls denticulated with points in their upper parts, and 



striated beneath — f inch. 

 umWellafum. . the upper margins of the whirls denticulated, 



the under ones crenulated and expanded in the teeth of the 



next whirl, no strise, top of the spire smooth — l^^ inch. 

 lamellosum. . turreted, subplicated ; distant transverse strise, 



base with three transverse lamellce — l^ inch. 



