﻿268 



EOCENE MOLLUSCA. 



lineis spiralibus paru/u eminentibus, undulatis, supra margines posticas exilissimis, crebris, 

 cateris distantioribus : aperturd oblongo-ovali (?), in canali brevi exeunti ; labro sub-recto ; 

 sinu lato, mediocriter prof undo, sub-trigono, media in margine collocato. 



Shell subulate, concentrically obscurely lined, almost smooth ; spire nearly 

 conical, elevated, equalling the aperture in length ; whorls six (exclusive of a rather 

 large, smooth pullus), depressedly convex, with gently sloping margins, widely chan- 

 nelled, slightly thickened round the suture, and girt by a narrow, raised band, 

 rounded on the upper surface, and traversed by a single, faint, elevated line ; the last 

 whorl is much contracted in front, and terminates in a wide, short, but distinct, canal. 

 The spiral lines are very faint, nearly obsolete, scarcely detracting from the otherwise 

 smooth surface of the shell ; over the margins they are close-set, but become more 

 distant over the middle and front parts of the whorls. The aperture is concealed 

 by the matrix, but, apparently, it is of a lengthened oval shape ; the outer lip, as 

 displayed by the lines of growth, is but slightly arched, nearly straight ; and the sinus, 

 which extends almost across the margin, is wide, moderately deep, and somewhat 

 triangular in form. 



The specimen figured is the only one I possess of this Pleurotoma ; the nearly 

 smooth surface, and tapering, conical spire, associated with the short, anterior canal 

 and marginal sinus, distinguish it, however, from all its congeners. 



Size. — Axis, 8-12ths of an inch nearly ; diameter, not quite 3-12ths of an inch. 



Locality. — Basingstoke. 



No. 191. Pleurotoma lissa. F. E. Edwards. Tab. XXVIII, fig. 5, a, b. 



P. testa brevi, lata, fusiformi, costellatd, concentrice obsolete sulcata, politd : spird 

 sub-conicd, dimidium totius testa vix aquanti: anfractibus planulato-convexis, postice 

 canaliculatis, lavibus, marginatis ; ultimo anfractu antice coarctato, in canalem brevis- 

 simum producto ; sulcis transversis rotundatis, distantibus, sulcis anterioribus perspicuis, 

 cateris obsoletis : aperturd obovatd ; labro arcuato, acuto ; sinu lato, fere semicirculari, in 

 margine collocato. 



Shell short, wide, fusiform, with a smooth, shining surface, longitudinally ribbed, 

 concentrically furrowed ; spire rather short, barely equalling the aperture in length ; 

 whorls, six exclusive of the pullus, flatly convex on the sides ; the posterior margins 

 smooth, deeply furrowed, and bordered round the sutural edge by a thick, raised band 

 rounded on the upper surface : the last whorl is slightly contracted in the front, and 

 produced into a short, very wide, canal ; the longitudinal ribs are vertical, short, thick, 

 rounded, smooth on the upper surface, and separated by spaces equalling the ribs 

 in breadth ; the ribs themselves are lost on the last whorl of the mature shell ; the 

 concentric furrows are rather wide ; they are rounded and perspicuous over the canal 



