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ART. XXII — 0?i the Osteology of the Read of Hippopotamus, and a Description of 

 the Osteological Characters of a New Genus of Hippopotamidce. 



By Joseph Leidy, M. D. 



The opportunity afforded of studying an entire skeleton of the animal, of which 

 two specimens of crania were described by Dr. Morton, under the name of Hippo- 

 potamus Liberiensis,* lately received from Africa, led me to an examination of the 

 cranial specimens of the large Hippopotamus, preserved in the collection of the 

 Academy, which has been confirmatory of the views of Desmoulinsf and Duvernoy,J 

 that two distinct species exist, usually confounded under the name of Hippopotamus 

 amphibius. 



But, granting that the two species alluded to are distinct, the latter name should 

 be retained for that species earliest known, which is that of Linnaeus, while the other 

 should preserve the name given to it by Desmoulins, of Hippopotamus Capensis, as 

 being the first applied. 



The materials which we possess for studying the osteology of the Hippopotamus, 

 are as follows ; 



HIPPOPOTAMUS AMPHIBIUS, Lin?!. 



Hippopotamus amphibius, p. aucto)-um : Vide Fischer, Synopsis Mammalium, p. 

 424 ; Schinz, Synopsis Mam., 2, 343. 



Hippopotamus Senegalensis, Z)e5/woM/m5 ; N. Bull, des Sci.de la Soc. Philom., 

 1825 ; Diet. Class. d'Hist. Nat., Hippopotamus. 



Hippopotamus typus, Duvernoy : Comptes Rendus, t. 23, p. 650. 



1. The head of a very old male ? From Guinea. Presented by twelve members of 

 the Society to the Academy. 



All the sutures of the head are entirely obliterated. In the upper jaw, on one side, 

 are the remains of four molars, and on the other, three molars, and these are worn 

 down nearly to the edge of the alveoli. The first permanent true molar had been 

 shed and its alveolus nearly obliterated. In the lower jaw, also, on one side, four 

 molars remain, and on the other, three, worn down nearly to the alveolar border! 

 The upper lateral incisors are unhappily lost in the specimen. 



* Proc. Acad. Nat. Sci., vol. 2, p. 14; Journ. Acad. Nat. Sei., vol. 1, 1849, p. 231. 

 •j-N. Bull, des Sci. de la Soc. Philom., 1825. Diet. Class. d'Hist. Nat.: Hippopotame. 

 \ Comptes Rendus, Oct., 1846. 



