PULMONATA. 117 
and numerous genera and sub-genera have, in consequence, been withdrawn by Gray, 
Guilding, Troschel, Pfeiffer, and others, on characters taken principally from modifi- 
cations of the operculum. The present genus was separated by Mr. Guilding, from 
Cyclophorus, for some shells from the West Indies; it is distinguished by the thick 
calcareous operculum, formed of two distinct layers. The animal, so far as it is 
known, resembles that of Cyclostoma. 
The recent species are not very numerous. Mr. Gray, in his Nomenclature of 
Molluscous Animals, &c., in the British Museum, part “ Cyclophoride,” gives a list of 
twenty-eight species, all of which are from the West Indian Islands, or from Central 
or South America. 
No. 67. CycLotus cinctus. F. 2. Edwards. Tab. X, fig. 1 a—e. 
C. testa conico-depressd, lineis tenuibus spiraliter cinctd; anfractibus quinque vel sex, 
rotundatis, ultimo paullo decurrenti : umbilico magno; apertura sub-circulari. 
This remarkably elegant shell is conical and somewhat depressed, formed of five or 
six rounded whorls, and ornamented with numerous, irregular, rather sharp, spiral, 
raised lines, some of which are more elevated than the rest; these lines are spread 
over the whole surface of the shell; but they are more crowded on the upper than on 
the under surface, and are very prominent in the umbilicus, where they are sometimes 
strongly decussated by the lines of growth. The last whorl is slightly decurrent; the 
aperttire is nearly round, with the peristome a little reflected, but not much so; and 
the umbilicus is very wide, being nearly one third of the diameter of the shell. 
Two or three detached opercula have been obtained by Mr. D’Urban, which present 
all the leading characters of the opercula of the living species; but, as yet, it cannot 
be determined to which of the two fossil species they belong. They are thick, 
testaceous, slightly concave externally, formed of five or six slowly enlarging whorls 
with the external fringe deeply grooved. One of them is represented by fig. 12 a—4, 
Tab. X. 
This species has hitherto been found only at Sconce, where it occurs rather plenti- 
fully; but specimens with the shell preserved are rare. 
Stze.—Axis, 5-10ths of an inch; diameter, rather more than 6-10ths of an inch. 
No. 68. CycLotus Nupus. Ff. #. Edwards. Tab. X, fig. 11 a—s. 
C. testa ovato-conicd, levi; spird mediocri; anfractibus quinis convexis: apertura 
rotundatd, umbilico parvo. 
A smooth ovately-conical shell, with a moderately elevated spire, formed of five 
convex volutions: aperture nearly circular; umbilicus narrow but deep. 
The surface of the shell in this species is perfectly devoid of ornament, a character 
