296 EOCENE MOLLUSCA. 
No. 220. Pxirurotroma opscurata. Sowerby. Tab. XXXII, fig. 1, a, 6. 
PLEUROTOMA oBsCURATA. Sow. 1850. Dixon’s Geol., &c., of Sussex, p. 184, t. 7, fig. 19. 
_ _ Morris. 1854. Cat. Brit. Foss., p. 270. 
P. testd angustda, turritd, omnino concentrice lineata, undulato-costatd : spird elevatd : 
anfractibus numerosis, convexiusculis ; postice canaliculatis, ad suturam unicd serie tuber- 
culorum cinctis ; antice coarctatis ; lineis concentricis crebris, exilibus, regularibus ; costis 
numerosis, brevibus, curvis, ad humeros pre-eminentibus: apertura ovali, in canali brevi, 
paullulo reflexo, exeunti; labro aliformi, ad humerum anguste et profunde sinuato ; 
columelld sub-rectd. — 
A long, narrow, turreted shell, ornamented with numerous curved ribs, and 
having the whole surface covered with raised, spiral lines ; the spire, which is formed 
of ten or eleven volutions, exclusive of the pullus, is much elevated, forming 3-5ths of 
the entire length of the shell; the whorls are flatly convex, and much contracted in 
front ; and the posterior margins are slightly channeled, and thickened round the suture, 
where they present a single row of oblique, oblong tubercles. The ribs are numerous, 
short, and curved, following the outline of the outer lip; they are thick, rounded, 
and prominent on the shoulders, imparting somewhat of a turreted character to 
the spire, and they taper rapidly as they cross the middle of the whorls, where they 
are lost ; the spiral, raised lines are thread-like, numerous, and irregular. The 
aperture is of a roundish-oval form, and terminates in front in a short, but distinct, 
rather wide, and nearly straight canal, having the anterior extremity slightly bent 
backwards ; the outer lip is curved, wing-shaped, with the front part much pro- 
jecting ; the sinus, which is placed on the shoulder, is of a narrow, deep, oblong 
form; the columella nearly straight, and crested by the reflexure of the canal. 
Size.—Axis, 1 inch and 3-12ths; diameter, rather more than 10-12ths of an 
inch. 
Locality—Bracklesham Bay. 
No. 221. Preurotoma uma. F. #. Edwards. Tab. XXXII, fig. 3, a—ce. 
P. testa elongatd, sub-turritd, longitudinaliter curvo-plicatd, concentrice scabro-lineatd, 
tuberculato-carinatd : spird elatd, obtusd: anfractibus planulatis, ad humeros angulatis ; 
postice concavis, ad suturam granulatis ; ultimo anfractu brevi, antice coarctato, in canali 
brevi obliquo, terminato ; plicis longitudinalibus numerosis, acutis, ad basin tendentibus ; 
