SIMIAD^E. 505 



some of the Baboons (Cynocephali) but not in all (the Mandrill and the 

 Drill for example), the nostrils are terminal and abrupt, giving a dog-like 

 appearance to the extremity of the upper jaw. Where the tail is 

 elongated, it acts an efficient part as a balancer to the animals in their 

 arboreal evolutions ; but where it is short, or only reaches to the heel, 

 its utility appears to be more limited, and it is carried in an arched form, 

 first rising from its base, and then sweeping down to, or toward, the 

 ankle. The characters, however, derived from this organ, considered with 

 regard to its length, are comparative, not positive ; and, on the circumstance 

 of the tail of one species being a few inches longer, or shorter than that 

 of another, no generic divisions can be established. 



An attentive and repeated examination of an extensive series of the 

 skulls of various species, assigned by naturalists to the several genera, Cer- 

 copithecus, Cercocebus, Macacus, and Cynocephalus, for the express purpose 

 of endeavouring to draw from them diagnostics, clearly distinguishing 

 each genus respectively, definite characters by which the generic place 

 of any species might be at once ascertained, has ended in no satisfactory 

 results. Setting aside the fifth tubercle on the last molar of the lower 

 jaw, common to the Cynocephali, the Macaci, and to the Collared and 

 Sooty Monkeys, assigned, by most naturalists, to the genus Cercopithecus, 

 the skulls failed to furnish, as they do in the Gibbons and Semnopitheci, 

 positive data of separation. It is true that, if a skull of one of the Cerco- 

 pitheci and of the Mandrill be placed together, the difference between them 

 is striking ; but these are two extremes of the chain, and the intermediate 

 links consist of a series of forms passing by gradations from the Cerco- 

 pitheci to the Cynocephali ; the depression of the skull and the develop- 

 ment of the muzzle, appearing, in a first stage, in some of the Cercopitheci, 

 exhibiting a progressive advancement in the Macaci (in several of which, 

 indeed, the depression of the cranium and the development of the 

 muzzle are extraordinary), and carried to an ultimatum in the Cynoce- 

 phali. With such a chain of links before him, the naturalist, looking at 

 the skulls alone, will find some difficulty in drawing his lines of generic 

 division, unless, indeed, he take into the account the character of the 

 last molar tooth of the Cercopitheci (with three exceptions), and their 

 habitat, in opposition to the character of the last molar of the 

 Macaci, and to their habitat (with one exception; viz., the Magot). 

 Habitat, it must be confessed, is in itself no generic character ; 

 nevertheless, by taking it into the account it aids the naturalist in 

 doubtful cases, and so far becomes valuable, as an adjunct, to trivial 

 or unimportant physical characters. Thus, independently of the 

 consideration of these points, several Indian Monkeys, of the genus 

 Macacus, as already stated, might be referred to the genus Cerco- 

 pithecus. 



VOL. I. 3 T 



