PROSOBRANCHIATA. 175 



of which the middle one is the largest and most prominent, and several transverse 

 raised lines behind. Fig. 4 b, 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 ditch 

 {V. dentata), which somewhat resembles the present species; but the ribs terminate 

 posteriorly in erect, pointed 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, 1 inch and a half ; diameter, three-quarters 

 of an inch. 



Localities. — Bracklesham Bay. French .• Monneville, Valmondois (fide Desh.) ; Les 

 Clergis, Acy (fideD'Orb.). 



No. 113. Voluta protensa. Sowerby. Tab. XXIII, figs. 5 a — c. 



Voltjta protensa. Sow. 1840. Min. Con., vol. vii, p. 5 ; t. 612, figs. 6, 7. 



V. testa fusiformi, protensa, transversim striata, in juventd obscure costatd ; spird 

 acuminata, apice acuto ■• anfractibus convexiusctdis, ad margines suturales depressis .- aper- 

 turd angustd, profunde emarginatd ; labro simplici, tenui, acuto ; labio angusto ; columella 

 pluries plicatd. 



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. 



