6 EOCENE MOLLUSCA. 
the siphonal or posterior side also is rather more distinct than in cwnezformis, and the 
anterior lateral tooth is rather narrower and more elongated ; but the ornamented exterior 
is the principal character that seems to justify its being placed in a separate specific 
position. 
5. Cyrena Forsesit, Deshayes. Tab. A, fig. 5 a, b. 
Cyrena Forsestt, Desh. An. sans Vert. du Bas. de Par., t. i, p. 510, pl. xxxvii, 
figs. 24—27, 1860. 
Spec Char. C. Testa ovato-trigond, subtransversd, inequilaterah, turgidula, posterius 
depressd, obtuse angulatd, transversim obsolete striata ; umbonibus prominentibus obliquis ; 
latere antico rotundato, postico acuminato ; cardine inequaliter tridentato, dentibus divari- 
catis ; dentibus lateralibus crassis inequalibus. 
Length, \xth of an inch ; height, 1 inch. 
Localities. Britam: Charlton. (8. Wood.) 
France: Sainceny. 
This has been separated, and I think justly, by M. Deshayes from Cyrena antiqua, 
Ferussac. Speaking of C. antigua, however, M. Deshayes says (‘ An. sans Vert. du Bas. 
de Par.,’ tom. 1, p. 510) that “M. Hébert en a recueilli de nombreux échantillons dans 
les environs de Dieppe ; elle est egalement en abondance dans les Lignites de Woolwich 
en Angleterre.” ‘This statement is, I think, an error as far as Woolwich is concerned, 
for I have not been able to see the true aztiqua from our own beds. 
My researches in the Woolwich beds at Charlton were confined to a large excavation 
that was open when I hunted it fifty years ago, and I have not since visited it. My 
specimens have, however, ever since been carefully kept with the localities attached, and 
I give them as undoubtedly genuine. 
6. Cyrena DunwicuiEnsis, Rickman. ‘Tab. A, fig. 14 a—e: 
Cyrena Dutwicmensts, Rickman. Quart. Jour. Geol. Soc., vol. xvii, p. 6, 1861. 
_ _— Edwards. Geologist, p. 210, pl. v, figs. 4, 5, 1860. 
— _— J. Lowry. Chart. Brit. Tert. Foss., pl. iv, 1866. 
Spec. Char. C. Testa oblongo-transversd, crassiusculd, inequilaterali, levigata vel 
obsolete striata; umbonibus minimis depressis viv obliquis; dentibus cardinalibus tribus, 
lateralibus inequalibus, elongatis, angustis, tenuissime striatis. 
