1872.] F. Stoliczka — On tlie Cyclostomacea of Penang. 2G3 



What Han ley 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 favilabris, hut it is impossible to form a good idea of the 

 character of the species from the insufficient illustration given. 



Cyclophobus Borneensis, var. PL X, Fig. 6. 



Metcalfe, Proc. Zool. Soc. 1851.— Pfeiffer in Chem. Conch., XIV, p. 362 and 

 Hon. Pneumon. p. 63. — Martens, Ost.-As. Esped., p. 136. — Reeve, Conch. Vol. xiii, 

 Cyclophorus, 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 strife, 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 funiculate. This 

 coloration is almost exactly like that of O. porphyriticus, as figured by 

 Pfeiffer in Chemnitz' Conchilienkabinet. 



One of the most important characters of Bomeensis 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. aqidla and perdix, with the last of which 

 Benson's C. porphyriticus has been considered as identical. E. v. Martens 

 already observes (1. 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 

 JBomeensis and perdioc. 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 Borneensis 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. 



