268 EOCENE MOLLUSCA. 
Tineis spiralibus parum eminentibus, undulatis, supra margines posticas exilissimis, crebris, 
ceteris distantioribus : aperturd oblongo-ovali (2), in canali brevi exeunti ; labro sub-recto ; 
sinu lato, mediocriter profundo, 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. Preuroroma utssa. F. 2. Edwards. Tab. XXVIII, fig. 5, a, 4. 
P. testdé brevi, lata, fusiformi, costellatd, concentrice obsolete sulcati, politd: spird 
sub-conicd, dimidium totius teste vix a@quanti: anfractibus planulato-convewis, postice 
canaliculatis, levibus, marginatis ; ultimo anfractu antice coarctato, in canalem brevis- 
simum producto ; sulcis transversis rotundatis, distantibus, sulcis anterioribus perspicuis, 
ceteris obsoletis: apertura obovatda ; labro arcuato, acuto ; sinu lato, fere semicirculart, 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 
