ORDER QUADRUMANA. 275 



the Malbrouc, the Callitrix, the Mangabey, and the Grivet. 

 With these last the forehead retreats abruptly, the anterior 

 part of the brain is altogether compressed, and this organ 

 receives no development but on the opposite side. On the 

 other hand, in the Mone, the Ascagne, and the Hocheur, 

 the forehead has almost a vertical elevation above the eyes ; 

 thus the facial angle which among the other Guenons varies 

 from 50° to 55°, will be with those latter from 60° to 65°. 

 In fact, on examining the naked skulls of the two groups, 

 the frontal bones of the one were found much more round- 

 ed, and the superciliary crests less strong, than those of the 

 other, and the same difference was also remarked in the 

 parietal bones. Our author observed these characters very 

 strongly impressed on the Mone, but fearing that they 

 might be only individual, he did not attempt to generalize 

 them. But having made similar discoveries respecting the 

 other two species, he came to the conclusion that they were 

 all peculiar to a group which, in reference to intelligence 

 and docility, might be considered as a link between the 

 Guenons and the Orangs. And he seems to think that 

 on a more attentive examination, other characters might 

 be recognised to distinguish them from the Guenons, and 

 such as might be employed with more facility than a few 

 degrees of difference in the projection of the forehead. It 

 was thus that the Guenons were at first separated from the 

 Macaques, only by the facial angle, but other characteristic 

 distinctions were discovered afterwards, to confirm the 

 essentiality and propriety of the first. 



To our author's short personal description of the two 

 last-mentioned animals we shall only add, that the Ascagne 

 is about fifteen inches in length, and the Hocheur about 

 twenty. The tails in both are much longer. The Ascagne is 

 also called the vaulting monkey, and is the blanc nez of 

 Buffon. The Hocheur is, however, properly the white- 

 nosed monkey, and differs from the Ascagne only by the 



