Dr. J. E. Gray on the Skulls of Potamochoerus. 47 



in the six or eight skulls of P. africanus and P. jyorcus 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, Jiarsh. 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. Edwardsii. 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, ivith an irregukirly rounded lower 

 edge ; the impression on the side of the forehead broad and trun- 

 cated behind, with a perpendicular edge ju^t 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 heeled on 

 the sides. 



Potamochoerus porcus^ Gray, Hand-Cat. B.M. tab. 23. fig. 1, c? . 



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. 



Potamochcerus africanus, G^r^y? Hand-Cat. B.M. tab. 23. 



fig. 2,(?. 

 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. 



