PROSOBRANCHIATA. 279 
Shell fusiform, elongated, turreted, concentrically lined: the spire pointed, elevated; 
whorls, seven or eight, without the pullus, slightly convex ; the posterior margins con- 
cave and plicated along the sutural edge, where they present two or three very fine, sharp, 
elevated lines ; the shoulders obscurely angulated, and ornamented with a series of 
rather distant tubercles, which on the early whorls are elongated, straight, and vertical, 
but on the last whorl become pliciform and curved ; the last whorl is much contracted 
in front and produced into a rather long and widish canal. The concentric lines over 
the posterior margins and shoulders are close-set, regular, slender, and not very 
prominent ; over the middle and front parts of the whorls they become more elevated, 
thicker, and more distant, with very fine, thread-like lines occasionally intervening. 
The aperture is of a narrow, elongated, oval form; the outer lip slightly arched, 
simple and smooth within; and the sinus, placed on the shoulder, is very wide, 
moderately deep, and triangular. 
A close comparison of the English shells with Belgian specimens has confirmed me 
in the conclusion at which Mr. Morris and myself had arrived when a series of the 
latter was first submitted to us by Sir Charles Lyell ; the shells from the two localities 
agree so closely that I do not feel any doubt of their specific identity. 
It is a rare shell in England, although apparently abundant in Belgium, and in case 
the position of the Limburg beds has been rightly determined, the occurrence of this 
species in England is attended with additional interest from its being another 
instance of the reappearance of shells of the London Clay period in the fauna of the 
Upper Eocene epoch under nearly analogous mineral conditions. 
Stze.—Axis, | inch and 7-12ths (40 millim.); diameter, 6-12ths of an inch (13 
millim. nearly). 
Locahties.—Highgate; Hampstead Railway Tunnel; Finchley; Muswell Hill. 
Belgian: Basele, Boom, Anvers (fide De Kon.), Rupelmonde, Gremittingen (fide Myst.) 
No. 204. Pxrevroroma Konincxn. Nysf. Tab. XXIX, fig. 15, a, 6. 
PLeuRnoToMa LauviGata. De Kon. (non Sow.) 1837. Cog. foss. de Basele, &c., p. 27, t. 1, 
fig. 5. 
— Konrncxir. Nyst. 1843. Bull. Soc. Géol. de Fr., vol. xiv, p. 454. 
= _— Nyst. 1843. Coq. foss., &c., de Belg., p. 517, t. 41, fig. 3. 
P. testé elongato-fusiformi, concentrice linedta: spird elatd, acuminata : anfrdactibus 
convexis, ad humeros in juventaé arcuato-plicatis, deinde inermibus ; ad suturam, lineato- 
marginatis ; ultimo anfractu antice gradatim attenuato ; lineis concentricis confertis, sub- 
regularibus : apertura oblongo-ovali ; canali antico, longiusculo, angusto; labro leviter 
arcuato, ad humerum sinuato ; sinu lato, mediocriter profundo, sub-trigono. 
A long, fusiform shell, ornamented throughout with concentric, raised lines; the 
spire, formed of six or seven volutions without the pullus, is pointed and much 
