Dr. J. E. Gray on the Skulls of Potamochcerus. 47 
in the six or eight skulls of P. africanus and P. porcus in 
the British Museum. 
The three species of this genus may be thus characterized 
by their skulls :— 
* Head and face varied with blackish ; fur elongate, harsh. Crest of 
the sheath of the upper canines elongate in the male. 
P. africanus. Nose of skull broad, flat at top, and keeled 
at sides ; lower edge of zygomatic arch regularly curved. 
South and Central Africa. 
P. Edwardsti.. Nose of skull narrow, rounded at top and 
upper margin of sides; lower edge of zygomatic arch sub- 
angular in the middle. (Plate IV. A.) 
Madagascar. 
** Head and face varied with white ; dorsal mane white. Crest of the 
sheath of the upper canines of the male shorter, broad. 
P. porcus. Nose of skull broad, flat at top, and keeled 
on the upper margin. 
West coast of Africa. 
They may be further characterized as follows :— 
* The zygomatic arch swollen out, with an irregularly rounded lower 
edge ; the impression on the side of the forehead broad and trun- 
cated behind, with a perpendicular edge just before the orbit ; 
the lower jaw with the perforation for the passage of the vessel 
under the space between the second and third lower grinders ; the 
front of the upper part of the nose flat, broad, rather keeled on 
the sides. 
Potamocherus porcus, Gray, Hand-Cat. B.M. tab. 23. fig. 1, 3, 
The lobe over the sheath of the upper canines of the male 
truncated, spreading outwards, and not reaching the callosity 
of the lateral ridge on the side of the nose. 
Potamocherus africanus, Gray, Hand-Cat. B.M. tab. 23. 
He 25 
The lobe over the sheath of the upper canines of the male 
elongate, adpressed to and reaching the callosity of the lateral 
ridge on the side of the nose. 
