﻿PROSOBRANCHIATA. 



245 



No. 165. Pleurotoma coarctata. F. E. Edwards. Tab. XXVIII, fig. 12, a — c. 



P. testa sub-fusiformi, costellatd, concentrice lineatd: spird elevatd, conoided .- 

 anfractibus convexiusculis, antice valde coarctatis ; justice unico sidco exaratis, ad suturam 

 tuberculatis ; costettis arcuatis, per-brevibus ; aperturd ovali, in canali brevi, latiusculo, 

 exeunti ; labro arcuato, intus dentato ; sinn sub-trigono, prof undo, in margine collocato. 



Shell elongate, fusiform, ornamented with longitudinal ribs and sharp, concentric, 

 raised lines : the spire, which is composed of seven or eight whorls, is rather conical, 

 pointed, and elevated, forming almost two thirds of the whole length of the shell. 

 The whorls are slightly convex, and suddenly much contracted towards the middle, 

 so as to be almost angulated ; a deep concentric furrow runs round the posterior 

 margin, the sutural edge of which is thickened and presents a single row of round or 

 oblong tubercles, varying in size in different specimens : the ribs are arched, sharp, 

 and rarely extend beyond the middle of the whorl. The aperture is oval and 

 terminates anteriorly in a short, wide canal ; the outer lip is arched, sharp-edged, 

 and armed within with two or three teeth, the largest of which is placed immediately 

 in front of the sinus ; the sinus itself is deep, sub-trigonal, and wide, occupying 

 the whole breadth of the margin. 



This Pleurotoma is smaller and narrower than P. innexa, to which it bears some 

 resemblance ; but the contracted whorls and short ribs distinguish it from that 

 species. 



Size. — Axis, rather more than 5-12ths of an inch ; diameter, 2-12ths of an inch. 

 Locality. — Highcliff, where it is not uncommon. 



No. 166. Pleurotoma microcheila. F. E. Edwards. Tab. XXVIII, fig. 8, a—f. 



P. testa parvd, crassd, fusiformi, nodulosd : spird obtusd : anfractibus convexiusculis, 

 ad humeros sub-angulatis ; marginibus posticis canaliculatis, ad suturam unicd serie tubercu- 

 lorum ornatis ; ultimo anfractu costellas angustas et tineas concentricas acutas, sese 

 decussantes, gerenti -. aperturd elongato-ovali, in canali per-brevi terminanti ; labro leviter 

 arcuato, acuto, intus incrassalo, plicifero ; sinu lato, sub-profundo, sub-trigono, anticd 

 in margine collocato. 



Var. product a, testa angustiori ; spird elevation ; lineis spiralibus eminentioribus. 



Shell small, thick, fusiform, and having the whole surface ornamented with 

 concentric rows of round, knob-like tubercles : the spire, which equals the last whorl 

 in length, is obtuse and pointed : the whorls, six or seven in number, exclusive of the 



