PROSOBRANCHIATA. 167 
narrow, obscurely channelled behind, and widely notched in front; the outer lip 
thickened within, thin and sharp at the edge ; inner lip moderately spread over the body- 
whorl, and presenting at the suture a callus-like thickening, which forms the left side of 
the posterior canal; the columella nearly straight, and furnished with two or three not 
very oblique folds, the front one of which is the most prominent. 
The present species approaches closely to V. geminata, but is much more turbinate, 
resembling in general form V. spinosa ; and the anterior tubercles are different in their 
character ; in the present species they are simply an enlargement of the ribs themselves, 
while in V. geminata, a transverse line runs round the shoulder, and rises into tubercles 
where it crosses the ribs; the aperture in / Forbesii is also narrow and more 
regularly ovate. This species is found in Hempstead Cliff; and I have dedicated it to 
the late much lamented Prof. E. Forbes, by whose researches the position of that 
formation in the tertiary series, so long misunderstood, has been ascertained. 
Size.—Axis, 7-10ths of an inch; diameter, 4-10ths of an inch. 
No. 106. Voxuta catva. Sowerby. Tab. XXI, figs. 6 a, 6. 
VoLuTa caLvA. Sow. 1850. Dixon’s Geol., &c., of Suss., p. 187; t. 7, fig. 28. 
V. testé pyriformi, antice transversim obsolete sulcatd, ceterum levi, ad basin vie 
emarginatd ; spird brevi, conicd, apice acuto: anfractibus angulatis, unicd sine spinarum 
donatis, superne concavis, marginibus anfractu precedenti adpressis : aperturd elongato-ovali ; 
labro tenui, simplicc ; labio parum effuso ; columella subrectd, bis vel ter plicatd. 
Shell pyriform, obscurely ribbed, slightly notched at the base, and presenting 
several faint, almost obsolete, transverse furrows in front, smooth elsewhere ; spire 
short, conical, with a small pointed apex: whorls angulated at the shoulder, and 
crowned with a single row of short, pomted tubercles; the margins pressed against 
the spire ; the space between the suture and the row of tubercles concave. The aper- 
ture of a lengthened oval shape ; outer lip thin, sharp-edged, smooth within ; inner lip 
very thin and but little spread out; and the columella furnished with two nearly equal 
folds in front, and a third very feeble one behind. 
The specimens are generally simply coronated ; but, in some instances, the elevated 
bases of the tubercles are prolonged into very short, faintribs. The angulated shoulder 
and the tubercles distinguish this species from the young shell of V. Selseiensis, with 
which only it might be confounded. 
Size.—Axis, 1} inch, nearly; diameter, 7-10ths of an inch. 
Locality Bracklesham Bay, where it is somewhat rare. 
