SMITH : MOLLUSCA OF TRINIDAD. 249 
In the first place, 2. ocerdentalts is larger, has a stouter 
appearance ; secondly, the riblets on the spire are further 
apart; thirdly, the penultimate whorl is not quite so gibbose; 
fourthly, the tooth on the columella is almost obsolete. 
I would also point out that in the Indian species the 
costulations on the penultimate whorl are much closer together, 
that is, more numerous than on the rest of the volutions, where- 
as in D. occidentale they are, if anything, further apart. The 
columellar denticle is small but quite distinct in D. Hu/ton/, 
and the mouth is not quite so circular as in the Trinidad shell. 
The dimensions given by Pfeiffer (Proc. Zool. Soc., 1852, 
p. 157) “Long. 24, diam. 1 mill.,” are not quite accurate judging 
from the types. The length is exactly 2 mills. only, whereas 
the Trinidad species is about 24. Although this appears a very 
small difference, in conjunction with the greater width it makes 
D. occidentale appear a distinctly larger shell.* 
47.—*Truncatella puichella Pfeiffer. 
48.—*Truncatella bilabiata Pfeiffer. 
49.—-*Truncatella subcylindrica Gray. 
50.—Taheitia reclusa (Guppy). 
51.—Cistula aripensis (Guppy). 
52.—Helicina nemoralis Guppy. 
Perhaps sufficiently distinct from 4. columbiana Philippi, 
with which it has been united by Bland (Ann. Lyc. Nat. Hist., 
N. York, vol. xi. p. 87). It differs in colour, and the body- 
whorl is a trifle more globose at the periphery. The opercula 
are identical. 
*Since these remarks were penned, my attention has been called by Mr. Sykes to 
Godwin-Austen’s account of the species of Dipjlommatina from the Western and Eastern 
Himalayas. In describing D. AHuttonz, he has notified the differences between the 
Trinidad shell and that species, and has imposed upon the West Indian form the name 
occidentalis. He does not, however, regard it as indigenous, observing that ‘‘it remains 
to be discovered from what hill-district of India the Trinidad form has been conveyed.” 
(Moll. India, p. 177). 
