Next we have the living African species, representing the subgenus Diceros, in which there are two horns but no front teeth.
The Peruvian species, Branchiostoma elongatum, with nearly eighty myotomes, cannot at present be assigned to its proper subgenus.
Other east African monkeys with a similar type of colouring, which, together with the wholly black west African C. satanas, collectively constitute the subgenus Guereza, may be included under the same title; and the name may be further extended to embrace all the African thumbless monkeys of the genus Colobus.
The members of the subgenus Guereza present a transition from a wholly black animal (C. satanas) to one (C. caudatus) in which the sides of the face are white, and the whole flanks, as well as the tail, clothed with a long fringe of pure white hairs.
From the North American grey foxes, constituting the genus or subgenus Urocyon, the true foxes are distinguished by the absence of a crest of erectile long hairs along the middle line of the upper surface of the tail, and also of a projection (subangular process) to the postero-inferior angle of the lower jaw.