224 E.vlernal Characlcrs of Ruminant Artiodactyla. 



strnctnre of the priiis, the presence of four mammpc, the 

 abseiiee of inguinal j^lantls, and tlie j)resciice on all lour 

 feet of Hask-slia|)e(l pi'dal glands uiih narrow exit passage 

 and small cirevilar orifice just behind tlic summit of the 

 interungual web. 



l^iff. 5. 







A. Muzzle and rbinarium of Hippotragns niyer from the front. 



B. The same from above. 



X4. 



Setting Addax aside, the genera discussed in this paper 

 may be distinguished as follows : — 



a. Rhinarium sculptured, with distinct philtrum reach- 

 ing lower edge of upper lip ; upper rim of dilated 

 nostrils swollen ; horns rising erect from head . . Hippotragus. 

 a'. Tlhinarium smooth, without philtrum, upper lip 

 entire ; upper rim of narrow nostrils not swollen ; 

 horns inclined backwards in the plane of the 

 forehead. 

 b. Preorbital gland present as a thickened pad of skin 

 like that of Hippolragus ; rhinai'ium shallow ; 



horns curved JEgoryx. 



b' . Preorbital gland absent; rhinarium deeper; 



horns straight Oryx. 



