92 GASTEROPODA OF THE INFERIOR OOLITE. 
strongly crenulate, keel of the body-whorl enormously so. Coste wide apart, 
scarcely traceable anteriorly, but strongly developed below the keel, though dying 
out towards the base of the shell. Spirals above the keel fine and numerous; few 
and wide apart (two or at most three) below the keel. The body-whorl, including 
the base, has ten spirals. 
Aperture subquadrate with an extremely short columella, strongly reflexed, so 
as to produce a notch of considerable depth. Hardly any trace of umbilicus. 
Relations and Distribution.—Kvidently related to the last-named species, P. 
calcar is extremely rare in the Sowerbyi-bed of Bradford Abbas. In this form we 
perceive the coarsest ornamentation of any species of Purpurina known to me. 
Inflata Group. 
10. Purrurina inFLata, Tawney, 1850. Plate II, figs. 2 a, 6,c; 2d,e; 2f. 
1873. Purpurtya inFLata, Tawney. Dundry Gasteropoda, p. 4, pl. iii, fig. 9. 
Bibliography, §c.—Mr. Tawney need not have apologised for making this 
species, which is much nearer to P. Sowerbyi, Waagen, than to P. coronata, Héb. 
and Desl., with which he tried to identify it. 
Description : 
Length of a well-grown shell. : . 24mm. 
Ratio of width to length : ; « 80% 00: 
Length of body-whorl to entire shell Z ~ faz LOO: 
Spiral angle ‘ a ee 
Shell ovate-globose ; spire about three- cient of ike entire length. Whorls five 
to six, tumid, but flattened posteriorly and markedly canaliculate. Body-whorl 
much inflated. The longitudinals or coste are numerous, regular, of moderate 
force, and with a slight slope from left to right. On the shoulder of the whorls 
each rib terminates in a slight spinous projection, forming a closely crenulated 
keel; the coste extend about half way down the body-whorl. The spirals are fine, 
numerous, and regular, but are not seen to extend over the flat area. 
Aperture ovate to semilunar, with a short and scarcely inflexed columella in 
the more adult specimens. In younger. specimens the anterior groove is better 
marked, and the umbilical slit is also more apparent. 
Relations and Distribution—This species may be regarded as typical of the more 
globular forms of Purpurina, which are found both in the Inferior Oolite of the 
Anglo-Norman basin, and also in the Callovian of Montreuil-Bellay. It is 
undoubtedly near to P. Sowerbyi, Waagen, but rather more tabulate. 
