1861.] " NEW SPECIES OF MAMMALS." 277 



Our specimen came from (he Bight of Biafra, Mr. Du Chaillu 

 says it is found in forests in the interior, and not in maritime plains 

 or flat country (p. 301). 



The specimen is without hoofs, ears, or tail ! 



PoTAMOCHCERUs ALBiFRONS, Du Chaillu, I. c. p. 301 ; Travcls, 

 t. 62 at p. 422, is P. penicillatus. Gray, P. Z. S. 1852, p. 12.9. 



This animal differs in the colour of the face from black to white. 

 Specimens of both varieties are in the collection. It is called the 

 Camaroon River Pig ; but Mr. Du Chaillu says it inhabits high table- 

 lands, both on the coast and at the head-waters of Fernando Vah. 



Manatus owenii, Du Chaillu, I. e. p. 367. 



I may observe that I cannot find any distinction between this and 

 the other African Manatees, which have been called M. senegalensis, 

 M. latirostris and M. voyelii (P. Z. S. 1857, p. 29). 



The African species are distinguished from the American one by 

 the larger size of the malar bone, and in the base line of the lower 

 jaw being more curved. In the American skull the lower edge of the 

 malar bone is nearly straight, with a moderate-sized rugose tubercle 

 in the middle. In the African skull the lower edge of this bone is 

 more or less produced, according to the age of the animal, forming a 

 rounded lobe, which is largest in the adult skull, and giving a nearly 

 semicircular form to the lower edge of the bone. 



The skulls of Mr. Du Chaillu's specimens exactly agree with the 

 figure of the skull of M. senegalensis in Blainville's ' Osteographie.' 

 The skull figured in the same work, named M. latirostris, is like our 

 younger one from the W. African coast. 



There are three skulls and imperfect skeletons in Mr. Du Chaillu's 

 collection ; the skulls appear to become broader, the central space on 

 the top of the head wider, and the tubercle on the under side of the 

 malar bone larger as the animal increases in age. 



The adult form is shown in Dr. Baikie's figure, P. Z. S. 1857, 

 p. 29, t. 51. 



Troglodytes gorilla. 



The first indication of the Gorilla which I recollect to have seen 

 was an imperfect skull (which had been used as a fetish) that was 

 brought from the Gaboon by Mr. Bowdich on his return from the 

 Ashantee Mission in 1817. This skull, it was then thought, might 

 be that of an adult Chimpanzee ; though Bowdich in his work 

 (pages 440, 441) mentions both the Inchego (Troglodytes niger) 

 and the Ingeua {T. gorilla^ as distinct kinds. 



Mr. Thomas Savage, the American Missionary at the Gaboon, 

 havhig obtained several skulls, in 1847 pointed out the distinction 

 between tlie skull of the Gorilla and the Chimpanzee ; and Professor 

 Owen followed up the subject, and figured two skulls in the * Pro- 

 ceedings of the Zoological Society' for 1848, observing that "som.e 

 scepticism might be expected as to the alleged specific distinction of 

 the large and small Chimpanzee by naturalists who had not been 



