304 GASTEROPODA OF THE INFERIOR OOLITE. 
Amberleya, though its affinities may possibly be stronger with Liassic forms of 
that genus than my own experience enables me to recognise. Certainly one 
would say that the Oolitic Amberleyas differ widely both from Hamusina and 
from Cirrus, more especially in the character of the aperture. The most marked 
difference between Amberleya, as developed in the Inferior Oolite, and Hamusina 
is the shortness of the columellar area in Hamusina, a feature which it shares 
with Cirrus. The probable relations of Hamusina will be more conveniently 
discussed when we consider the possible position of Cirrus itself. 
238. Hamusina Damust, Gemmellaro, 1878, var. “Babylonica.” Plate XXIV, fig. 12. 
1878. Hamusiya Damest, Gemmellaro. Faune Giuresi, &c., p. 338, pl. xxvi, figs. 
39—41. 
Description (British variety) : 
Length : 5 : 3 . 35 mm. 
Height of body-whorl to total length : . (302100: 
Spiral angle : . : . 40°. 
Shell sinistral, thin, conical, turrited, without umbilicus. Spire acute, 
consisting of seven or eight whorls, keeled towards the base, and slightly 
hollowed out towards the centre. The ornaments are somewhat rugose ; close 
to the posterior margin in each of the more adult whorls is a zone of tubercula- 
tions ; below this are some fine undulating spirals, their number increasing with 
each successive whorl; a little above the dominant keel is another zone of 
tuberculations, each tubercle being connected with a corresponding one in the 
posterior zone by a rugose axial rib sloping from right to left; these ribs are less 
strong in the penult, and are almost effete in the body-whorl; growth-lines, 
sloping from right to left, pervade the entire shell. 
The body-whorl is angular, with a flattish base, becoming subconvex towards 
the aperture; the ornamentation is substantially as in the spire-whorls, but the 
fine, undulating spiral lines are more numerous; these decussate with axial 
striz. So likewise in the base. The aperture is rounded on the columellar 
side, the columella being extremely short and incrusted, but the outer lip is 
angular, and drawn out laterally. 
Relations and Distribution.—The details of ornamentation differ considerably 
from Gemmellaro’s type, the principal difference being that in the English specimens 
the keel is more anterior. The smoothness of the base in Gemmellaro’s specimen 
was most probably due to the accidents of conservation, since it is not probable 
that a shell whose sides are so rugose should possess a perfectly smooth base. 
