246 EOCENE MOLLUSCA. 
pullus, are slightly convex and angulated at the shoulders ; the posterior margins rather 
wide, deeply channelled, apd bordered by a series of closely-set, knob-like tubercles ; 
the shoulders present a single row of oblong tubercles, divided by a concentric sulcus, 
and from these tubercles arise narrow, curved costellz, which extend almost to 
the very front of the whorl, and are decussated by sharp, concentric, raised lines, 
not quite so prominent as the costellz, forming small tubercles at the points of 
decussation ; the costella and concentric lines, in the earlier whorls, are nearly 
concealed by the succeeding whorl, and are only perfectly seen on the body-whorl. 
The aperture is of an oblong-oval form, terminating in a wide, short canal ; the outer 
lip is but slightly arched, sharp on the edge, and thickened and strongly plicated 
within ; the sinus, which is placed in front of the margin, is wide, rather deep, and 
sub-trigonal in shape. A variety occurs in which the shell is narrower, the spire 
relatively longer, and the concentric lines more prominent. 
This seems to be a well-marked species, of which I have not been able to find a 
foreign representative. 
Size.—Axis, 4-12ths of an inch; diameter, 2-12ths of an inch. 
Localities. —Highcliff, where it is found rather abundantly, Alum Bay (No. 29, 
Prestwich), Barton. 
No. 167. Pievrotoma pissimiLis. F. £. Edwards. Tab. XXVIII, fig. 7, a—e. 
P. testé parva, crassa, rugose costatd, omnino concentrice lineata: spird brevi, obvusd, 
nodulosd: anfractibus convexiusculis, ad humeros sub-carinatis, postice sulco profundo 
spiraliter exaratis, marginatis ; costis brevibus, latis, rotundatis ; lineis concentricis plus 
minusve numerosis, per-elevatis, denticulatis: aperturd oblongo-ovali, in canali brevi, 
latiusculo exeunti ; labro sub-recto, acuto, intus unicam plicam dentiformem gerenti ; labio 
angustissimo ; sinu lato, profundo, trigono, in margine collocato. 
Shell small, thick, coarsely ribbed, concentrically lined: the spire wide and 
rather short, being less than two fifths of the whole length of the shell: the whorls 
rather convex, slightly carinated at the shoulders, and bordered round the sutural 
margin by a sharp, elevated, ridge-like line, the space between which and the 
shoulder is traversed by a deep, round furrow, in which two or three feeble concentric 
lines are seen. The ribs are few in number, very short, broad, rounded, and separated 
by narrow furrows ; they become nearly obsolete, and frequently altogether lost on 
the last whorl; the concentric lines are sharp, much elevated, more or less numerous 
in different specimens, and generally denticulated by the lines of growth. The 
broad, short, posterior terminations of the ribs, left exposed by the overlapping of the 
succeeding whorls, resemble tubercles, and give a coarsely nodulous character to 
