NEWTON : CONCHOLOGICAI, FEA1 URES OF LENHAM SANDSTONES. 79 



Collectiojis — 



M.P.G., No. 440. 

 B.M. (Graham Wallas). 



Fam. RINGICULID^. 



RiNGICULELLA LENHAMENSIS Sp. nOV. [Plate 3, fig.S. 2 1, 22]. 



Riiigicula ventricosa var. Reid : Mem. Geol. Surv. United King- 

 dom, 1890, p. 255, noil J. de C. Sowerby. 



Diagnosis — 



Testct ovato-elongata vel subcylijidracea, Icevigata ; spira acuta, 

 conoidea ; anfractihis ^-6, subinfiatis ; snturis canaliadatis ; 

 columella infra biplicata ; labro marginato, non crenato ; bast 

 eniarginata. 



Dimensions — 



Length ... ... ... ... gto ii millimetres 



Diameter ... ... ... ... 5 to 7 ,, 



Reinai'ks — 



This fossil, besides being referred to by Mr. Reid as a "gigantic 

 variety" of Ringicula ventricosa, was further recognised as "perhaps 

 new species." 



It is an unusually large example of the Ringiculidre, and appears 

 to differ in this way from other forms of the family, as well as in its 

 more or less cylindrical contour, the possession of an elongate and 

 nearly parallel-sided body-whorl, and the presence of a generally 

 smooth surface throughout, only obscure longitudinal markings being 

 visible without any evidence of spiral striations. The species should 

 not be confused with Sowerby's R. ventricosa, which is of smaller 

 size, different contour, and moreover spirally ornamented. It differs 

 also from the recent Marginella auriculata of Menard ( = Vohita 

 buccinea Brocchi), which may be either smooth or furnished with 

 distant obsolete spiral sculpture, besides being of larger dimensions 

 and having a relatively narrower longitudinal axis. The absence of 

 crenulations on the inner surface of the outer lip would suggest, how- 

 ever, that this fossil had certain affinities with the modern species, 

 such forms being included in Sacco's ^genus Ringiculella, which was 

 founded on Menard's shell from the Mediterranean, previously quoted. 

 The largest specimen, as explained by a gutta-percha model, exhibits 

 both a dorsal and ventral view, the latter giving details of the aper- 

 ture, although the columellar plications are obscure, these being better 

 expressed in a smaller example. 



Distribution — 



Lenham Beds ... ... ... ... Britain. 



I Moll. Terz. Piemonte, 1892, part 12, pp. 16 — 33. 



