﻿314 



EOCENE MOLLUSCA. 



shoulders a series of slightly curved, irregular crenulations, more or less closely set in 

 different specimens ; the posterior margins are very wide, -covering the preceding 

 whorls up to the shoulders ; they are deeply channelled, and much thickened round 

 the sutural edge, so as to form a broad, elevated band, which is crossed by numerous 

 narrow, vertical plications, corresponding with the crenulations on the shoulders ; the 

 whole surface of the margins, and also the shoulders, are covered with fine, concentric, 

 raised lines, which are most prominent over the sutural band ; the body whorl is flatly 

 convex, nearly conical, and terminates in front in a wide, short, but distinct canal, 

 rather deeply notched at the anterior extremity. The concentric bands are thick and 

 very prominent, rounded on the upper surface, and rather distant ; the intervening 

 spaces are flat, and traversed, in some specimens, by one or more thread-like raised 

 lines, and in others by flattened bands, similar in character to the principal bands, but 

 much narrower and less prominent. The aperture is of an oblong-oval form ; the 

 outer lip much arched, almost semicircular, thin and sharp on the edge, and smooth 

 within ; the sinus, which is placed on the shoulder, is deep and not very wide, with 

 nearly parallel margins ; and the columella is slightly twisted, and presents near the 

 middle an obscure callus. 



This strongly marked species is, I believe, peculiar to Bramshaw ; at least I have 

 not met with it elsewhere. In its general aspect and the character of the ornamenta- 

 tion, it strongly resembles the Soissonnais shells referred by Deshayes to Solander's 

 P. colon; but, as I have already pointed out, the sinus in those shells is placed in the 

 marginal furrow, and not on the shoulder, as in the present species. 



Size. — Axis, rather more than 1^ inch ; diameter, 7-12ths of an inch. 



No. 239. Pleurotoma hemileia. F. E.Edwards. Tab. XXXII, fig. 13, a, b. 



P. testa fusiformi, idrinque sub-conicd, transversim fasciolatd: anfractibus ad humeros 

 obtuse angidatis, in juventdplicatis, deinde lavibus ; antice planulatis, postice declivis, paulo 

 concavis, adsuturam concentrice lineatis ; caterum lavibus ; fasciolis transversis sub-distan- 

 tibus, parum elevatis, interstiliis concavis ; ultimo anfractu ad basin emarginaio : aperturd 

 angustd, sub-quadratd, in canali patulo, indistincto, exeunte ; labro leviter arcuato ; sinu ad 

 humerum collocato, lato, prof undo, marginibus sub parallel is ; columella leviter contortd. 



Shell fusiform, rather narrow, presenting somewhat of the appearance of two 

 cones placed base to base, transversely furrowed and banded, but with the surface 

 smooth and shining : the spire, formed of seven or eight volutions, is elevated, equalling 

 the aperture in length. The whorls are obtusely angulated at the shoulders, round 

 which, in the very young state, they present a series of regular, closely set, 

 long, narrow, vertical plications, which gradually become more and more faint as 

 the shell is enlarged, and ultimately disappear on the fourth or fifth whorl, after 



