PROSOBRANCHIATA. 175 
of which the middle one is the largest and most prominent, and several transverse 
raised lines behind. Fig. 44, taken from a French specimen, is introduced for com- 
parison, and to shew the perfect shell. 
In general appearance, this Volute resembles V. maga ; but it is quite smooth ex- 
-cepting where a few faint lines traverse the base; the spire is turreted, more slender, 
and tapering; and the ribs more numerous and more prominent. 
Mr. Sowerby has described* a Volute from the tertiary formation in Cutch 
(V. dentata), which somewhat resembles the present species; but the ribs terminate 
posteriorly in erect, pomted tubercles, the surface of the shell is concentrically striated, 
the outer lip is plicated within, and the columella presents only two, nearly equal, pro- 
minent folds. 
Size.—According to M. Deshayes, axis, | inch and a half; diameter, three-quarters 
of an inch. 
Locahties—Bracklesham Bay. French: Monneville, Valmondois (fide Desh.) ; Les 
Clergis, Acy (fide D’Orb.). 
No. 113. VouuTa prRoTENSA. Sowerby. Tab. XXIII, figs. 5 a—e. 
VoLUTA PROTENSA. Sow. 1840. Min. Con., vol. vii, p. 5; t. 612, figs. 6, 7. 
V. testd fusiformi, protensd, transversim striata, in-juventd obscure costatd ; spird 
acuminata, apice acuto: anfractibus convexiusculis, ad margines suturales depressis: aper- 
turd angustd, profunde emarginata ; labro simplici, tenui, acuto ; labio angusto ; columella 
pluries plicata. 
Shell fusiform, elongated, transversely striated, obscurely ribbed in the young state ; 
spire elevated, being as long as the aperture, and terminating in a small, pointed apex : 
whorls six or seven, rather convex, depressed round the sutural margin, and having 
the edge pressed against the spire: aperture narrow, deeply notched at the base ; 
outer lip simple, thin, and sharp-edged ; inner lip very narrow; columella straight, 
furnished with six or seven distant oblique folds ascending to the top of the columella ; 
the fold in front is the largest and most prominent, the others thread like, and nearly 
equal. 
This appears to be a well-marked species, quite distinct from all the other Eocene 
Volutes. 
Size.—Axis, 2 inches; diameter, 6-10ths of an inch. 
Localities. —Chalk Farm, Whetstone, Potter’s Bar. 
* Grant’s Geology of Cutch, Geol. Trans., 2d series, vol. v, p. 322; t. 25, fig. 26. 
