1872.] F. Stoliczka — On the Oyclostomacea of Penang. 263 
Wliat Hanley figures, in Conch. Indica, pi. xlviii, fig. 4, as C. Malay - 
anus from the Shan States, has, I believe, nothing to do with the Penang 
shell, though it may represent a variety of Siamensis, or a peculiarly 
depressed one of flavilabris, but it is impossible to form a good idea of the 
character of the species from the insufficient illustration given. 
CxcLOPiiORtrs Bobneensis, var. PI. X, Fig. 6. 
Metcalfe, Proc. Zool. Soc. 1851. — Pfeiffer in Chem. Conch., XIV, p. 362 and 
Mon. Pnenmon. p. 63, — Martens, Ost.-As. Exped., p. 136. — Reeve, Conch. Vol. xiii, 
Cyclnplwrus, pi. xii, fig. 50. 
The Penang variety of this species is flatter, somewhat sharper keeled 
at the periphery, and with a slightly more expanded lip than exists in any 
Bornean specimens I saw, but the general type of the shell is unmistakable. 
It is a rare species on Penang hill ; I found during many days search only 
two adults* and one young. The former are covered with a rather thick 
dark brown cuticle, marked with very fine transversely oblique and also with 
spiral striiE, by which a kind of a very minute granulation is produced. 
There is a row of larger brown spots along the suture, while the rest of the 
whorls is densely variegated with reddish brown, most conspicuous after 
a partial removal of the cuticle, and the keel is slightly funieulate. This 
coloration is almost exactly like that of O. porphyriticus, as figured by 
Pfeiffer in Chemnitz’ Concliilienkabinet. 
One of the most important characters of Porneensu is the straight- 
ness and slight concavity of the inner portion of the peristome along the 
umbilical margin, followed by the basal portion being somewhat produced. 
This character also occurs in C. aquila and perdix, with the last of which 
Benson’s C. porphyriticus has been considered as identical. E. v. Martens 
already observes (l. cit. p. 135) that it is impossible to give a well defined 
diagnosis of C. aquila, as the species is very variable and readily passes into 
Porneensu and perdix. I have not a sufficient series of authentic specimens 
from different localities, but the few from Penang, Singapore and Borneo 
entirely support the view expressed by E. von Martens, and make it most 
probable that the different names noticed only refer to the principal varieties 
of one and the same species. It is unquestionable that even in true Bornean 
specimens the upper convexity of the whorls is sometimes greater sometimes 
less, the keel on the last whorl sharp, or obtuse, or again almost obsolete, 
and in consequence of this the sharp edged last whorl passes into an 
obtusely angular or even slightly rounded one, and that with these variations 
the height of the entire shell must naturally vary. 
I possess Singapore specimens of Porneensis which exactly agree with 
C. porphyriticus, as figured by Pfeiffer in Chemnitz, and as this figure is 
* The figured specimen is the more depressed one. 
