192 EOCENE MOLLUSCA. 
Nec Conus DEPERDITUS, Broce. 1814. Conch. Foss. Sub-app., vol. ii, p. 592, No. 10, t. 3, fig. 2. 
nec — — Bors. 1821. Oritt. Piem., p. 14, No. 13. 
nec — — Brongn. 1823. Terr. tert., &c., du Vicentin, p. 32. 
nec — — Bast. 1825. Desc. des coq. foss., &c., de Bord., p. 39. 
nec — — Bronn. 1831. Italiens tertiargeb., p. 12, No. 5. 
nec — — Pusch. 1837. Polens Paleont., p. 115, No. 2. 
nec — — Grat. 1838. Cat. zool., &c., de la Gironde, p. 47, No. 422. 
nec — —_— Ib. 1838. Tabl. statist. &c., de Adour, t. 19, No. 22. 
nec — —_ Ib. 1840. Conchyl. foss., &e., de l Adour, t. 2, figs.18, 19. 
nec — _— Sismon. 1847. Synop. method., &c., Pedem. Foss., p. 44. 
nec — — Sow. 1850. Dixon’s Geol., &c., of Sussex, p. 108, t. 8, fig. 9. 
C. testa turbinatd, elongata, levi, ad basin transversim obsolete sulcata ; spird promi- 
nuld, acutiuscula : anfractibus numerosis, angustis, angulatis, marginibus posticis depressis, 
strias tenues concentricas gerentibus ; ultimo anfractu regulariter conoideo, sursum dilatato : 
apertura angusta ; labro tenui, simplici, valde arcuato, postice profunde emarginato. 
Shell oblong, turbinate, with a moderately elevated mucronate spire, variable in 
height, but rarely exceeding a fourth part of the whole length of the shell, and ter- 
minating in a smooth, conical pullus, formed of three volutions; whorls numerous 
(10—12, exclusive of the pullus), bluntly angulated at the shoulders, nearly straight 
on the sides, with the posterior margins depressed, narrow, somewhat concave, and 
concentrically lined; the concentric lines are usually four or five in number, sharp, 
irregular, unequal, separated by moderately deep, rounded furrows, and frequently 
decussated by the lines of growth. In some specimens the early whorls are very 
finely tuberculated on the shoulders, and concentrically sulcated ; the tubercles, how- 
ever, disappear after the third or fourth volution, and the shoulders are afterwards 
smooth and simple: the concentric furrows also become gradually effaced on the 
posterior portion of the whorls as the shell approaches maturity, and ultimately are 
altogether lost, leaving only a few very obscure waved furrows traversing the base of 
the shell. The last whorl is conical, much attenuated in front, with nearly straight 
sides ; the aperture is linear and narrow; the outer lip, which is thin, sharp-edged and 
much arched, presents a shallow but wide curvature at the posterior extremity. 
M. Deshayes states that traces of the natural colouring are sometimes found in the 
French shells, consisting of narrow, transverse bands, occasionally interrupted by 
irregular, zigzag patches, following the direction of the lines of growth. Similar traces 
appear, though very rarely, in the English specimens. 
This species appears to be confined to the middle eocene strata; for the shells 
from Ronca (Vicent.), described by Brongniart as C. deperditus, D’Orbigny regards as 
belonging to a distinct species, which he has named C. Brongniarti, and to this species 
the shells described by Bellardi from the nummulitic beds at Nice, probably are also 
referrible. Subsequent comparison has shown that specific differences also exist in 
the various shells from the more recent deposits which have been referred to the 
