300 ROTELLIDA. 
lar; peritreme continuous, inner lip thickened and arcuate, outer 
lip with the margin thickened; umbilicus crenulate. Japan. 
C. crenellifera, A. Ad. (1xxix, 92). 
MoRcHIA, A. Ad. Shell obliquely ovate, depressed, widely 
umbilicated, convex above, flat beneath; whorls rapidly 
increasing, the last dilated, ascending and embracing the other 
whorls as far as the apex; aperture oblong, oblique, somewhat 
horizontal, dilated below, narrowed above; peritreme continuous, 
thickened. Japan. C. obvoluta, A. Ad. (xxix, 93). 
CIRSONELLA, Angas. Shell minute, globosely turbinate, smooth, 
narrowly umbilicated ; aperture circular, peritreme continuous, 
slightly thickened. C. australis, Angas (Ixxix, 94). 
Discopsis, Folin. Shell discoidal, depressed, umbilicated ; 
margins of the oblique aperture canaliculately joined upon the 
penultimate whorl. 2sp. W. Africa. 
Faminy ROTELLID A. 
‘Shell more or less lenticular, polished; umbilical region covered 
by a large, convex, subvitreous callus. Operculum thin, cor- 
neous, ciliated on the outer edge; animal with rudimentary 
rostrum ; frontal lobes greatly developed. 
Roretia, Lam. 
Etym.—Diminutive of rota, a wheel. 
Syn.—Globulus, Schum. Umbonium, Link. 
Distr.—20 sp. India, China, Japan, Phiiippines, N. Zealand. 
R. Zelandica (xxix, 95, 96). Fossil. Devonian—. 
Shell depressed, lenticular, the spire depressed conical; aper- 
ture semiorbicular, outer lip sharp; base with a convex, rounded 
umbilical callus. 
Animal. The lateral fringe of the foot is distinct, with three 
tentacular filaments on each side; at the front of the right side, 
near the base of the tentacles, it is produced into an oblong, 
fleshy lobe. The right tentacle is the larger and free, with an 
oblong, compressed lobe on its hinder side which has an indis- 
tinct indication of an eye; the left tentacle is smaller and partly 
attached to the upper side of the left eye-pedicel, which is cylin- 
drical, bearing a very distinct eye, and furnished with a large, 
membranous expansion attached to the whole of its length on 
its left side, and which is fringed at the edge. - This frontal 
appendage, when the animal is alive, is folded on itself to form 
a tube, which has caused it to be mistaken for a siphon. 
ETHALIA, H.and A. Adams. (Pseudorotella, Fischer.) Whorls 
convex, smooth or transversely striated; columellar lip termi- 
nating anteriorly in a callosity. Scarcely differing from the 
typical group. &. Guamense, Quoy (1xxix, 97). 
HAPLOCOCHLIAS, Carpenter. Shell like Collonia, but not pearly ; 
