136 PROCEEDINGS OE THE SCIENTIFIC ASSOCIATION. 
double peristome, convex whorls, and a thin operculum of 
few whorls with prominent edges. 
Diplomatina Huttoni Pfeiffer. 
Pfeiffer , Proc. Z. S. 1851 ; Conspect ., No. 181 ; Iconogr ., t. 48, 
f. 36, 37 ; Cat. Phanerop. B. Jf., p. 86. 
A minute pupiform sinistral shell of about 5 whorls, with 
riblike longitudinal striae and a continuous double peris- 
tome. Length 2\ mill., breadth 1 mill. 
This curious little shell is found near the Maraeas water- 
fall. Its occurrence in Trinidad is very singular ; for the 
genus has hitherto only occurred in India, and the present 
species was described by Pfeiffer from Indian examples. It 
seems very improbable that this species could have been in- 
troduced ; and as Nnnea licolor is also common to Trinidad 
and India, it would be of interest to arrive at a true expla- 
nation of the matter. I may state, however, that there is 
scarcely as yet absolute certainty that the present shell is 
identical with its Indian analogue. 
I was led to the discovery of this shell by information, 
supplied me by my kind friend Mr. Thomas Bland, F.G.S.* 
of New York. 
Order Scutibranchiata. 
Helicina Lamarck. 
Helicina fPerennaJ lamellosa Guppy. 
Ann. Mag. Nat. Mist. 3 ser. vol. xix., p. 260. 
A small depressed light reddish-brown thin Helicina orna- 
mented with spiral ridges which bear free lamellar edges 
especially towards the carinate periphery. Height 2% mill., 
greatest diameter 4% mill. 
For this little shell, found at the Ootoras Islets, I have 
constituted provisionally a new sub-genus under the name 
of Perenna. 
