264 F. Stoliczka — On the Cyclostomacea of Penang. [No. 3, 
authentic, being taken from the type in Benson’s collection, I would not 
hesitate to add porpliyriticus as a synonym of Borneensis. Sowerby’s origina 
figures of perdix (at least fig. 127 in Tlies. vol. I) and of aquila scarcely differ, 
and both very well agree with the form of Borneensis as usually obtained at 
Singapore, having the whorls above rather inflated and the periphery very ob- 
tusely angular. The same applies to Chemnitz’s figure of aquila, while 
that of perdix, after Tenaserim specimens, very closely corresponds with 
one of my Penang specimens of Borneensis, except in having a greenish 
cuticle. Reeve’s' figure of aquila is probably taken from a specimen obtained 
inland north of Singapore ; those specimens are particularly fine and pro- 
bably most aberrant from the type shell, which Reeve figured as Borneensis 
while his figure of perdix has the whorls as round as Siamensis, and though 
it may belong to the same species as represented by Sowerby’s figure 128 m 
Thes. vol. I, I do not think that it can at all be referred to the Borneensis 
group, because it appears to want the peculiar straightness of the inner 
portion of the peristome. 
The solution of this question of identity depends now upon a com- 
parison of the type-specimens of Sowerby’s G. perdix and aquila with a good 
series of typical Borneensis, as represented in Borneo, near Singapore, 
Malacca and Penang ; for it will also determine the nomenclature of the 
latter species. . , , , 
The animal of the Penang variety of Borneensis is uniform pale brown 
with a slight pinkish tinge, and covered with numerous flat greyish warts ; 
the foot is rather narrow and very long posteriorly, the lateral basal portion 
below the pedal row is warty, not sulcated ; head slightly darker than the 
body, tentacles blackish near the tip ; eyes on small bulgings, surrounded by 
a pale ring ; mantle greyish, thick near the margin. There is scarcely 
a noticeable difference in the size ol the sexes. 
The only other species of Cy'clophorus which I have to mention, and which 
has been described from Penang, is C. Pfefferi of Reeve. It belongs to the 
section of C. tuba with a very much expanded peristome, without any 
markedly straight inner, or produced basal portion. E. v. Martens (1. cit. 
p. 134) states that it is probably not constantly different from C. tula, but, 
setting aside the more inflated whorls of the latter species, I believe, Pfeiffei i 
also differs from the last by a much more rapid increase of the volutions. 
In this point, as well as in the flattened and angular shape of the whorls, 
it, however, quite agrees with expansus, and a large specimen of this last 
from Tenaserim scarcely at. all differs from Reeve’s illustration ; I would, 
therefore, be inclined to regard Pfeifferi as identical with expansus. 
