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EOCENE MOLLUSCA. 



This species approaches nearly to P. granata ; but the depressed and deeply con- 

 cave margins and rounded shoulders of the whorls give a peculiar character, by which 

 it may readily be distinguished. It also presents a close resemblance to a Pleurotoma 

 from the upper and middle Eocene deposits of Germany, figured by Beyrich (' Die 

 Conchjlien des norddeutschen Terticirgebirges,' tab. xxix, fig. 4) ; but descriptions by 

 that author of the Pleurotoma; figured by him have not been yet published, and 

 without them, or a comparison of the shells themselves, it is unsafe to express any 

 opinion as to the identity of the two species. 



Size. — Axis, ll-12ths of an inch, nearly; diameter, rather more than 4-12ths of 

 an inch. 



Localities. — Highgate, Potter's Bar, Chalk Farm. 



No. 234. Pleurotoma granata. F. E. Edwards. Tab. XXXI, fig. 7, a — c. 



P. testa oblongo-fusiformi, furritd, undique transversim granoso-lineatd : anfractibus 

 depresso-convexis, ad humeros obtuse carinat is, noduloso-crenatis ; marginibus posticis latis, 

 profunde cavatis, ad suturam incrassatis, Mneatis, plicatis ; ultimo anfractu antice sub- 

 conico, in canali lato, brevi, desinente ; lineis transversis supra margines et humeros 

 anfractuum exilibus, numerosis, regularibus ; supra medias partes crassioribus, intequalibus, 

 lineis majoribus minoribusque alternantibus ; omnino lineis incrementi elegantissiwe granu- 

 latis : aperturd ob-ovatd ; labro tenui, valde arcuato ; sinu lato, mediocriter prof undo, ad 

 Jmmerum collocato ; columella contortd, callosd. 



A broad, fusiform shell, the whole surface of which is beautifully ornamented with 

 finely granulated, concentric, raised lines ; the spire, formed of five or six volutions 

 exclusive of the pullus, is turreted, pointed, and moderately elevated, not quite 

 equalling the aperture in length. The whorls are bluntly and obscurely keeled round 

 the shoulders, on which they present a series of rather closely set, oblong, obliquely 

 curved plications, variable in size in different specimens, and frequently lost on the 

 last whorl ; the posterior margins are wide, embracing the preceding whorls nearly 

 up to the shoulders, deeply channeled, thickened and fineiy plicated round the suture, 

 where, occasionally, they are girt with one or two raised lines more prominent than the 

 rest. The suture itself is deep and very perspicuous, owing to the great width of the 

 margin of the whorl. The last whorl is flatly convex and much contracted towards the 

 front, whence it tapers nearly regularly to the base, presenting somewhat of a conical 

 form ; and the anterior canal is wide and short, but distinct. The concentric lines over 

 the margins and shoulders of the whorl are numerous, regular, very slender, and thread- 

 like ; over the middle and front parts they are thicker and more prominent, closely set, 

 and unequal, larger lines alternating with smaller ones ; all are very regularly and closely 

 granulated by the lines of growth. The aperture is of a wide, oval form ; the outer lip 

 thin and sharp on the edge, and much arched ; the sinus, which is wide, moderately 



