HAMUSINA. 305 
Nevertheless the more salient features of the British and Sicihan shells 
approximate sufficiently to justify our regarding the two forms as varieties of one 
species. 
Our best specimens occur in the Murchisonex-zone of Babylon Hill. Hence we 
might name this form H. Damesi, var. Babylonica. It is also found sparingly on the 
same horizon at Stoford and Bradford Abbas. Modifications of ornament induced 
by solvents are apt sometimes to produce rather puzzling results in this species. 
239. Hamusina Oppetensis, Lycett, 1857. Plate XXIV, fig. 13 (Coker variety), 
fig. 14 (type refigured). 
1857. Turbo Opprtensis, Lycett. The Cotteswold Hills, p. 127, pl. iii, fig. 8. 
Cf. also Turzo Bertuexort, d’Orbigny. Prodrome,i, p. 248; and Terr. Jur., vol. ii, 
p. 337, pl. ceexxviii, figs. 7 and 8. 
Bibliography, §c.—Lycett observes that this is a remarkable species, resembling 
Turbo Bertheloti in its general figure and sinistral spire, but the latter has a 
double row of tubercles, and is destitute of the transverse ribs. As the result of 
a careful examination of the only three available specimens from the Cotteswolds, 
Iam forced to conclude that the strong transverse (axial) ribs shown in the 
original figure, and also in Pl. XXIV, fig. 14, of the present work, are not structural 
features. The real ornamentation is more truly depicted in the large shell from 
Coker (fig. 13); but the Cotteswold specimens show it more or less, though the 
ornaments have been variously modified by mineralisation and development from 
a hard and unkindly matrix. As so often the case, the “type” is an unfortunate 
specimen, calculated to mislead alike the author, the artist, and the reader. 
The subjoined description of Haiusina Oppelensis is based partly on Cotteswold 
and partly on Coker specimens. It would seem to be a very general rule that 
species of Gasteropoda, as they are followed from Dorset-Somerset into the 
Cotteswolds, diminish greatly in size. The sinistral Gasteropods are no exception 
to the rule. 
Description : 
Length : . 30—50 mm. 
Height of body-whorl to total Terie . 39 to 40 : 100. 
Spiral angle about ; . 46°, 
Shell sinistral, thin, conical, without aanpilicus, Apical conditions unknown. 
Number of whorls about eight ; these are somewhat convex towards the centre, 
and upon the convexity is a single row of tubercles; at the anterior extremity is 
39 
