294 KOCENE MOLLUSCA. 
and shoulders of the whorls are rather thick, equal, regular, and not very prominent ; 
over the middle they are elevated, more distant, separated by concave spaces as 
wide as the lines themselves, and granulated; the last whorl is much contracted 
in front, and terminates in a wide and short, but distinct, canal. The aperture is 
widely ovate ; the outer lip but slightly arched, thin, and sharp-edged, and smooth 
within; the sinus is moderately deep, rather wide and triangular in form, and 
placed on the shoulder. 
The present Pleurotoma closely resembles P. monerma, but the plications on the 
shoulders of the whorls are very distinct in character, and the transverse lineation in 
this species is bolder, coarser, and more closely set; the aperture is more widely oval, 
and the sinus also is neither so deep nor so wide. These differences appear to be 
constant, for although possessing a good series of each species, I do not find specimens 
presenting intermediate characters, and in a comparison of the two series the eye at 
once recognises the distinctions. 
Size-—Axis, 8-12ths of an inch; diameter, 3-12ths of an inch. 
Locality.—Highcliff. 
No. 218. PLeuroroma aBnormis. F. £. Edwards. Tab. XXX, fig. 14, a, bd. 
P. testa sub-turritd, sub-conicd, longitudinaliter costatd, omnino concentrice sulcatd: spird 
productd, obtusiusculd: anfractibus convexiusculis, postice canaliculatis, suturd undulata, 
simplici divisis ; ultimo anfractu in canali angusto, sub-obliquo terminato ; costis sub-dis- 
tantibus, longis, rotundatis, postice obliquis, ad humeros angulatis, antice curvis, attenuatis ; 
suleis numerosis, sub-equalibus: apertura ob-ovatd; labro leviter arcuato, acuto; sinu 
latissimo, minime profundo, triangulari, ad humerum collocato. 
A turreted, nearly conical shell, longitudinally ribbed, and having the whole surface 
covered with concentric furrows: the spire rather obtuse and much produced, being 
nearly half as long again as the aperture. The whorls, eight or nine in number, are 
very slightly convex, channeled round the posterior margin, and separated by a 
simple suture, rendered undulating by the ribs of the preceding whorl. The ribs are 
rather numerous (twelve or thirteen), depressedly convex on the upper surface, 
long, extending from the suture to the canal, and separated by spaces equalling the 
ribs in width ; on the margin the ribs are very oblique, but they are bent at a slightly 
obtuse angle when they reach the shoulder, whence they are prolonged, and become 
much attenuated towards the front of the shell, forming a gentle curve corresponding 
with the outline of the outer lip. The concentric furrows are numerous, regular, 
moderately deep, rather narrow, and separated by bands somewhat wider than the 
furrows, and rounded on the upper surface. The aperture is nearly oval, and 
terminates in front in a short, slightly oblique, and narrow canal; the outer lip is 
