12 EOCENE MOLLUSCA. 
Spec. Char. M. testa tenui, ovato-oblongd, obliqud, gibbosd, levigatd, subcarinaté, 
valde inequilaterali, siphoni-regione latiore ; margine ventrali incurvatd, margine dorsali 
conveatusculd ; striis accretionis notatd. 
Shell thin, ovately oblong, oblique, gibbous, smooth or with visible lines of growth, 
subcarinated ; very inaquilateral, with siphonal region the broader; ventral and dorsal 
margins curved, but not parallel. 
Length, 2 inches. 
Localities. Wighgate (Wetherell), Newnham? (Prestwich). 
Mr. Sowerby, in ‘ Min. Conch.’ above referred to, considers this as doubtfully identical 
with the Paris basin shell, but thinks it probable it may be the same as JZ. modiolus of 
Brocchi. 
In the first part of ‘Coq. foss. des Env. de Par., t.i, p. 256, M. Deshayes has 
rejected the British fossil from among his synonyms on account of its dissemblance, but 
he has admitted it with a mark of doubt in his second part (Descr. des An. s. Vert., t. 2, 
p- 25). Iam unable to throw any light upon this disputed point, and have therefore left 
it with the name originally given by Mr. Sowerby, but I fully agree with the French author 
that it cannot be united to WZ modiolus, Linn. M. Deshayes says his shell very closely 
resembles an oriental species which Mr. Hanley has named MWodiola Metcalfei, except that 
in;the recent shell the dorsal edge is more elongated ; but it is not so in our fossil, which 
bears a very strong resemblance to the Indian shell, and I think it probable the three may 
be united under one name. ‘There is in the recent British species and Crag fossil, 
M. modiolus, considerable variation, more so than is exhibited between the Eocene fossil 
and the Indian species. 
17. Moprtona sutcata, Lamarck. ‘Tab. XIU, fig. 11. 
Mopiona sutcata. Lam. Ann. du Mus., t. vi, p. 222; and t. ix, pl. 17, fig. Ll a, 6. 
-= a Desh. Coq. foss. des Envy. de Par., t. i, p. 258, t. 39, figs. 9, 10. 
— — Morris. Catal. Brit. Foss., p. 212, 1854. 
_ — Desh. An. sans Vert. du Bassin de Par., t. 11, p. 15, 1860. 
Myvritus suucatus. Desh. Ency. Méth. Vers., t. iil, p. 566, No. 26, 1830. 
Spec. Char. “ Testd clongatd, spathulata, obliqud, depressd, anticé posticéque longi- 
ludinaliter sulcatd, in medio levigatd ; umbonibus minimis; margine antico brevissimo, 
crenulato.”? 
Shell elongate, spathulate, oblique, depressed, both sides striated or radiated ; central 
portion smooth ; umbones small; anterior margin (pedal region) very short, crenulated. 
Length, $ths of an inch. 
Localities. Barton (Hdwards). 
France, Grignon, Parnes (Deshayes). 
