458 Journal of the Asiatic Society of Bengal. [NS., XIV, 
All that can be siid is that the shell is perhaps more like that 
of certain abnormal forms of Planorbis'! than any other. It is 
thin and translucent, of a pale brownish or yellowish colour, 
coiled sinistrally, extremely elongate and narrow, especially in 
C. terebra, C. austent and the Japanese form; the whorls are 
few in number and the suture so deep and broad, especially 
narrow and is surrounded in all the species by a peculiar 
almost membranous rim. Benson describes the soft parts as 
follows :—“Animal, Tentaculis duobus filiformibus, obtusis, 
oculis majoris inter tentacula sitis, proboscideque mediocri 
munitum ; pallio labia testae haud transeunte ; pede brevi, longi- 
tudinem aperturae vix superante.”’ 
iving specimens of the Japanese species* agree in every 
respect with this description. Unfortunately specimens brought 
in spirit to India met with an accident and dried up complete- 
ly before an examination could be made. With the aid of dilute 
glycerine, however, we have been able to soften a specimen 
sufficiently for us to see the external characters quite clearly. 
The edge of the mantle is thickened and highly vascular, 
but there is no external branchial fold on the ventral surface. 
The tentacles are elongate, tapering and filiform; they have 
the eyes situated at their base internally. The outline of the 
foot is closely similar to that of the aperture of the shell. The 
snout is broad and rounded, and apparently does not project 
beyond the anterior margin of the foot. ; 
e have extracted the radula from a Japanese specimen. 
It resembles that of Ancylus in general structure, but has also 
certain resemblances to that of some species of Succinea. 
Hdd OG 
1G. 1.—Radular teeth of Ja | i a= cen 
$ panese species of Camptoceras. 
tral tooth. b=lateral teeth. c= veri teeth. 
aH 
Transversely the rows of teeth are feebly angulate. The 
central tooth, though relatively large, is well differentiated from 
— 
fig : ho eats ‘¢ Mollusca” in Bronn’s Thier-Reichs, III, pt- 3+ P- te 
* We have refrained from discussing the shell-characters oe 
; ay tote, Dn 
that in most points they are almost exactly intermediate betwee 
a and C. austeni. We think that there can be no doubt as 
generic identity of these three forms. 
