374 Mr. C. J. Gahan on the Prionidous 
Type in the collection of the Zoological Museum of the 
Imperial Academy of Sciences at St. Petersburg. 
This species is evidently aquatic, like Crossopus fodiens, 
the fringes of the manus and pes being even better developed 
than in that species; but in all generic characters it agrees 
with those of the genus Sorevr. While agreeing with Sorex 
palustris from the adjoining continent of America in external 
characters, it differs from it in the proportions of its teeth, 
resembling in this respect the section of which S. vulgarts is 
typical, while S. palustris agrees with those represented by 
S. vagrans. No better proof could be afforded of the useless- 
ness of retaining Neosorex as a distinct genus for the Ameri- 
can species characterized by the possession of swimming- 
fringes in the digits, while the tail is simple, as in Sorex. 
These species are in fact aquatie forms of the genus Sorea. 
LITt.—Note on the Variation of the Mandibles in the Males 
and Descriptions of the Females of the Prionidous Genera 
Priotyrannus and Cacosceles. By C. J. Ganan, M.A., 
Assistant, Zoological Department, British Museum. 
THE variation in the form of the mandibles within the same 
species of certain genera of Prionide has doubtless been 
known to many entomologists who have studied the family, 
though no special attention seems to have been called to it. 
The variation itself is probably of greater degree than has 
been hitherto suspected. Lacordaire, at least, in his treat- 
ment of the Prionide, does not give evidence of his knowledge 
of any great variation. 
The subject has lately been brought under my notice while 
working out the Longicornia of a collection made by G. F. 
Hampson, Esq., in the Nilghiri Hills, South India. 
One species was represented by four specimens, three of 
which have mandibles so different in form from the fourth, and 
in other respects are in such complete agreement with it, that 
I was at first led to believe that I had to deal with the two 
sexes. But all four proving to be males, it then seemed to 
be a case of variation in the mandibles parallel to that which 
occurs in many genera of Lucanide (Odontolabis, for example). 
The species was referable to the Prionus mordax of White, 
on which Thomson has founded his genus Priotyrannus. The 
single specimen with incompletely developed mandibles agrees 
with the male type from which White described the species. 
