238 EOCENE MOLLUSCA. 
Nec PLEUROMOMA ATTENUATA, Desh. 1824-37. Deser. des coq. foss., &c., vol. ii, p. 483, t. 68, 
figs. 6, 8. 
nec — — Dujar. 1837. Mém. Soc. Géol. de France, vol. 1, p. 291, t. 20, 
fig. 22. 
P. testa elongato-fusiformi, turritd, costatd, undique spiraliter lineatd: spird elevatd, 
acuminata ; anfractibus angulatis, unicd serie nodorum spiniformium, costas coronantium, 
armatis ; marginibus posticis latis, declivis, ‘concavis, ad suturam pauxillum incrassatis, 
tenuiter crenulatis ; ultimo anfractu antice sensim attenuato, in canali longiusculo, lato, 
terminanti ; costis brevibus, sub-distantibus, rotundatis; lineis spiralibus numerosis, in 
marginibus tenuibus ; ceteris inequalibus: aperturd lanceolata ; labro arcuato ; sinu lato, 
subtrigono, in margine collocato. 
Shell elongated, fusiform, turreted, longitudinally ribbed, and ornamented with con- 
centric raised lines: the spire, formed of eleven or twelve volutions exclusive of the pullus, 
is much elevated and pointed; the whorls, angulated at the shoulders, are gradually 
attenuated towards the base, assuming an almost conical form; the body-whorl termi- 
nates in a wide, moderately long canal, rather deeply notched at the anterior extremity ; 
the posterior margins are wide, slightly bent towards the preceding whorls, channeled 
along the middle, thickened at the sutural edge, and bordered by two thickish, promi- 
nent, raised lines, granulated or feebly plicated by the lines of growth. The ribs are 
rather distant, short, oblique, rounded, and terminate at the shoulder in large, trans- 
versely compressed, spiniform tubercles, the bases of which are frequently prolonged 
backwards half-way across the posterior margin. The whole surface of the whorls is 
covered with close-set concentric raised lines, which are thread-like and nearly equal 
on the margins, but irregular and unequal over the middle and front parts of the 
whorls; one or two more or less slender lines intervening between thicker and more 
prominent lines: the whole surface is roughened by the lines of growth, which in the 
Bracklesham Bay specimens are very prominent, and give a coarse, rugged character 
to the shell. The aperture is of a long, narrow, lanceolate form ; the outer lip mode- 
rately arched; and the sinus, which is wide, not very deep, and sub-trigonal in shape, 
is placed in the margin. The columella is nearly straight, and presents a large promi- 
nent crest or comb at the anterior extremity. 
M. Deshayes (/oc. cit.) has given the specific name aftenuata to certain shells from 
the older eocene beds of France, quite distinct from the present species, to which, in 
point of priority, the name belongs ; and Dujardin has fallen into the same error with 
regard to a Pleurotoma from Touraine. D’Orbigny, in his ‘Prodrome,’ has distin- 
guished the French eocene shells by the name své-attenuata, and the miocene shells by 
that of pseudo-attenuata. 
Size.—Axis, 4 inches, nearly; diameter, 1 inch and 2-12ths. 
Localities —Although Mr. Sowerby (Dixon’s ‘ Sussex,’ p. 102) and Mr. Morris 
