OTtt^—tfOLLTJSCA OF TRINIDAD. 
20 
Subclass Prosobranchiata. 
Tbis subclass includes the greater portion of the marine 
gasteropoda. I am by no means confident of tbe correct- 
ness of tbe classification of tbe mollusca bere referred to 
that subclass, but as I am unable at present to bring for- 
ward a better arrangement, I have adopted tbe present one 
provisionally. 
Order Pbaneropneumona. 
Operculate terrestrial bfollusca witb seven-ranked toetb. 
Cyclotus Guilding 1840. 
Terrestrial Operculata witb solid depressed widely- um- 
bilicated shells having a circular aperture closed by an or- 
bicular operculum externally concave witb a central nucleus 
and numerous whorls having raised margins. 
O O 
Cyclotus translucidns Sowerby. 
C-yclostoma translucidum Sotcerby , Proc. Zool. Soc. 1843, 
p. 29. 
n ,, ib. Thes. Conch, p. 106, no. 46. 
t. 23, f. 4. . 
Aperostoma translucidum, Pfeiffer , Teitschr. f Mall. 1847. 
p. 104. 
Cyclotus translucidus, Pfeiffer , Mon. Phanerop.-p. 20. 
it „ Cat. Phanerop. B.M. p. 9. 
„ trinitensis, Guppy, Ann. § May. Nat. Hist. 3 se r* 
tol. xiv, p. 245. 
A smooth light straw-colored opaque shell with a large 
nearly circular operculum of seven whorls found in abun- 
dance on one of the Cotoras Islets, and near Savana Grande. 
It occurs more sparingly in many other districts. 
-This species is found in Venezuela. 
Height 15 mill., greatest diameter 22 mill. 
