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EOCENE MOLLUSCA. 



The close resemblance which this Pleurotoma presents to P.granata, both in form 

 and in ornamentation, would lead to its being regarded rather as a variety of, than 

 as distinct from, that species; but the narrower and less concave margins, and the 

 simple, rounded shoulders of the whorls, the more conical form of the spire and of 

 the last whorl, and especially the deep, oblong sinus, distinguish it. 



Like P. rotundata and P. granata, this species presents a close analogy with 

 certain shells from the lower Eocene deposits of Germany, figured, but not as yet 

 described, by Beyrich (' Norddeutschen Tertidrgeb.' tab. xxix, fig. 2) ; but on the 

 grounds before mentioned, it would be hasty to assume the identity of the English and 

 German shells. 



Size. — Axis, 10-12ths of an inch ; diameter, 4-12ths of an inch. 

 Localities. — Highgate, Potter's Bar. 



No. 236. Pleurotoma ljeviuscula. F. E. Edwards. Tab. XXXII, fig. 9, a, b. 



P. testa elongato-fusiformi, sub-turritd, Jceviusculd : anfractibus convexiusculis ; ad 

 humeros in juventd tuberculatis, deinde simplicibus, postice et antice transversim lineatis, 

 catcrum lavibus ; marginibus posticis canaliculatis : aperturd oblongo-ovali, in canali angusto, 

 brevi, exeunte ; labro leviter arcuato, tenia ; sinu lato, breviusculo, sub-trigono, ad humerum 

 collocato. 



Shell elongated, fusiform, nearly smooth ; the spire, formed of six or seven volu- 

 tions, is rather thick and pointed, and is nearly as long as the aperture. The whorls 

 are slightly convex, and in the early stages of growth present on the shoulders a series 

 of close-set, oblong tubercles, which become obliterated on the third or fourth whorl, 

 after which the shoulders are smooth ; the posterior margins are ornamented by three 

 or four concentric, raised lines ; of these the one nearest the suture is sharp and 

 ridge- like, and more prominent than the others, and immediately in fiont of this the 

 margin is traversed by a rather deep, narrow channel : the other marginal lines are 

 feeble and somewhat obscure ; the middle of the whorls is smooth ; the front parts 

 and base are covered with numerous, close-set, raised lines, rounded on the upper 

 surface ; these lines are irregular and unequal, fine lines alternating with thicker ones. 

 The aperture is of an oblong-oval form, and terminates in front in a narrow, short, 

 but distinct canal ; the outer lip is thin, smooth within, and but slightly arched ; 

 and the sinus, which is on the shoulder, is wide, not very deep, and somewhat three- 

 cornered. 



The smooth surface of this Pleurotoma is not a common character, and entitles it 

 to specific distinction. 



Size. — Axis, rather more than 7-12ths of an inch; diameter, 5-24ths of an inch. 

 Locality. — Brockenhurst. 



