﻿PROSOBRANCHIATA. 



303 



laribus, aqualibus : aperturd oblongo-ovali ; labro fere recto ; sinu lata, mediocriter pro- 

 funda, rotundato, ad humcrum, collocato. 



Shell elongated, fusiform, concentrically furrowed; the spire nearly conical and 

 moderately elevated, not quite equalling the aperture in length. The whorls, seven or 

 eight without the pullus, are depressedly convex and are smooth and without ornament 

 on the shoulders ; the posterior margins, which slope very gently backwards, are 

 traversed by a rather wide and deep concave furrow, and their sutural edge is simple ; 

 the last whorl is girt round the shoulder by a narrow, riband-like band, scarcely 

 elevated above the surface ; it is much contracted towards the front, and terminates 

 in a wide and short, but distinct, canal, notched at the anterior extremity. The con- 

 centric furrows are numerous, not very deep, even, and regular, and are separated by 

 ridges of equal width with themselves, and rather depressed on the upper surface. 

 The aperture is of an oblong-oval shape ; the outer lip is very little arched, nearly 

 straight, and situated on the shoulder ; and the sinus is wide, moderately deep, and 

 rounded at the extremity. 



This species is closely analogous with P.flexuosa (Miinst.), of which, perhaps, it 

 may be considered a variety ; but the posterior margins are wider and more broadly 

 furrowed, and the whorls do not present the curved costellse, nor are they bordered 

 round the suture by the sharp, elevated line, found in that species. 



Size. — Axis, 9-12ths of an inch, nearly; diameter, not quite 3-12ths of an inch. 



Localities. — Clarendon, Alum Bay (Stratum No. 4, Prestwich), and Potter's Bar. 



No. 228. Pleurotoma variata. F. E. Edwards. Tab. XXXT, fig. 11. 



P. testa elongatd, angustd, sub-cglindricd, sub-lurritd, longitudinaliter obsolete plicatd, 

 transversim irregulariter sulcata -. spird elatd, bi-trienles totius testa fere aquanti : anfrac- 

 tibus convexiusculis ; marginibus posticis paullulo cavatis, ad suturam granoso-lineatis ; 

 sulcis transversis supra margines jjoslicas et humeros anguslis, confer lis ; caderum latioribus, 

 distantioribus : aperturd ob-ovali, in canali brevi, obit quo exeunte ; labro valde arcuato ; 

 sinu lato, pjrofundo, ad hurnerum collocato. 



Shell long, narrow, somewhat turreted, and ornamented with obscure longitudinal 

 plications, and irregular concentrical furrows : the spire is obtuse, sub-c)lindrical, and 

 much produced, being nearly double the length of the aperture. The whorls are depres- 

 sedly convex ; the posterior margins, which slope gently backwards, are very slightly 

 furrowed, and are bordered round the suture by a single row of very small granula- 

 tions. The transverse furrows over the posterior margins and shoulders of the whorls 

 are narrow, shallow, and irregular, those near the suture being more closely set than 

 the others ; over the middle and front parts of the whorls the furrows are broader and 



