262 F. Stoliczka — On the Cyclostomacca of Penang. [No. 3, 
Group.— CYCL O STOMA CM A. 
Fain. Crcr.ornoRTD.u. Genus, Cxclophobus, Montf. 
Ctclophobiis Mjllatanits. PI. X, Figs. 1-5. 
Benson, A. and M. N. H., 2nd ser., vol. x, p. 269. Pfoiffer, Monograph Pneumo- 
nopomornm. Bnpph I, p. 42. Reeve, Conch, vol. xiii, Cydophorus, pi. I, fig. 2. 
This is a tolerably common species on Penang, being generally distri- 
buted from near the seashore to the top of Penang bill, about 2500 feet. 
I have given a whole series of illustrations in order to shew the diffe- 
rent stages of growth, although Reeve’s figure is a very good representation 
of an adult specimen. 
Ordinarily the shell is smooth, exhibiting only the usual finer and 
stronger striae of growth, hut the pale brown and thin cuticle when well 
preserved is spirally striated, the striation being more conspicuous in young- 
er shells than in more adult ones. 
Young specimens of only two or three volutions have very conspicuous 
transversely oblhpie cuticular striae, and in this stage the shell with its 
angular last whorl perfectly resembles Pfeiffer's Cyclostoma (Leptopoma) 
Birmanum,* which is no doubt either a young of the present species or of 
C. Siamensis. Nearly all young Cyclophori have these transverse filiform 
striae of the cuticle. 
When larger the shell scarcely differs from that of C. Cantori, Benson, 
of which figures are given by Pfeiffer in Chemnitz’ Conch. -kab., and also by 
Reeve. I have not obtained in Penang any such small specimens with fully 
developed lips as are represented in those figures, but I have observed that the 
usual difference of the male being often slightly smaller than the female 
also exists in the present species, and an illustration of a nearly full 
grown male, given in fig. 4, comes very close to that of Reeve. Judging 
from the difference observed in the size of the sexes of other species, 
as is for instance very often the case in O. Pearsoni, I am inclined 
to the opinion that the specimens described as G. Cantori are males 
of C. Malay anus, the latter being females. If this were the case, the 
former name would have priority over the latter, but even if the expla- 
nation of sexes would not in this case hold good, I believe that the form 
described as Cantori can scarcely be looked upon as anything else than a 
smaller race of Mai ay anus, and vice versd. 
The animal is grey, darker on the head, brownish on the tentacles, pale 
towards the tip of the rostrum and at the basal edges of the foot. 
* Chemnitz’ Conchy lienkabinet, Yol.IX, p. 363, and Mon. Pneum. Suppl. II, p. SB. 
