292 EOCENE MOLLUSCA. 
callus, with the curved extremity of which it forms a wide, transverse groove, running 
into the sinus; the sinus is placed on the shoulder, and is wide, very deep, and 
triangular in form. 
Specimens occur rather plentifully at Highcliff, constituting the variety raphium, 
in which the shell is smaller and narrower, the spire more slender and_ pointed, 
the margins of the whorls not so concave, and the concentric lines are moderately 
distant, even, regular, and smooth. Another variety, moniligera, is also found, but 
more rarely, in which the spire is longer, the elevated line bordering the posterior 
margins of the whorls is coarsely granulated, and the median transverse lines are 
more distant and more prominently denticulated. 
In the general aspect of the shell and the character of the ornamentation, this 
Pleurotoma closely resembles the middle Eocene forms of P. denticula; but the 
callosities which present themselves on the inner surface of the outer lip indicate a 
peculiar modification of the excretory tube protruded through the sinus, which 
apparently entitles the present Pleurotoma to specific distinction. 
Size.—Axis, 8-12ths of an inch; diameter, 3-12ths of an inch. 
Localities—Barton, Alum Bay (Stratum No. 29, Prestw.), Highcliff, where it is 
abundant, and Brook. 
Section II. Shells fusiform. 
B. Sinus on the shoulder. 
6. Canal short or indistinct. 
‘ continued. 
No. 216. Pievroroma monermMa. Jf. #7. Hdwards. Tab. XXXII, fig. 1, a—e. 
P. testé angusta, elongatd, turritd, undique concentrice lineatd: spird elevatd, in 
longitudine bitrientes totius teste fere equanti, acuminatd: anfractibus convexiusculis, 
postice concavis, ad suturam bi-lineatis, ad humeros sub-angulatis, noduloso-plicatis ; ultimo 
anfractu per-brevi, in canali lato, indistincto exeunti ; plicis numerosis, verticalibus, arcuatis, 
utrdque extremitate sub-nodulosis ; lineis concentricts supra margines posticas et humeros 
anfractium exilibus, confertis, equalibus, ceterum prominentibus, distantibus, irregularibus : 
apertura oblongo-ovali; labro arcuato, simplici; sinu lato, profundo, sub-trigono, ad 
humerum collocato. 
Shell narrow, elongated, turreted, and ornamented with concentric, raised lines, 
which cover the whole surface ; the spire, formed of seven or eight whorls, exclusive of a 
smooth, conical pullus of three volutions, is pointed and much produced, being nearly 
twice the length of the aperture. The whorls are slightly convex and obscurely angu- 
lated at the shoulders, where they present a series of regular, rather closely set, vertical 
plications, transversely furrowed along the middle, and swelled into small tubercles at 
