CEBUS 65 



each side. The orbits are large and close together, the nasals being 

 quite narrow ; the f rontals contain air cavities, and there is no external 

 meatus to the ear. The incisors incline slightly forward, and are 

 shorter than the canines; the molars have four cusps, and on the 

 crowns there are two transverse ridges and one oblique, the last going 

 from the front inner cusp to the hind outer cusp. In the often great 

 variation in the color of their fur, witnessed among the members of 

 the various genera of the Primates, there is probably no genus whose 

 species exhibit a more extreme diversity of hues than do those belong- 

 ing to Cebus, and in some cases it would appear that each individual 

 possessed the power of selecting the color of its own dress, and the 

 taste for diversity of hues has been so wide, that it is not easy some- 

 times to find members of the same species alike. This instability of 

 color has been one of the greatest, if not indeed, the greatest obstacle 

 to all investigators in the determination of the species, for with the 

 majority of the earlier Authors, color was the chief character for a 

 distinct specific rank, cranial differences having been little regarded, 

 and consequently the number of species was largely increased. The 

 fact that great variability in color among individuals of the same 

 species, often from the same locality, was not known ; or perplexed at 

 the great diversity of hues exhibited by his examples, and unable to 

 explain the problem, an Author would, happily, sometimes, place all 

 his specimens in one species, geographical distribution receiving little 

 consideration. Unfortunately the latter method was not often adopted, 

 and multiplication of species has been with many writers more the 

 rule than the exception, and the synonymy consequently greatly 

 increased thereby. Another difficulty with the Cebi has been, and is 

 still to-day, that Mammalogists have been obliged to content them- 

 selves with the descriptions given by Authors, (few types being usually 

 accessible), often inadequate, brief and insufficient, and many have 

 been misled by these, and wrong conclusions reached. Then again 

 types have disappeared, and the brief description originally given was 

 totally insufficient for any one to decide what the species really was, 

 or, (as the Author of this work has found to be the case in too many 

 instances), neglect for their proper preservation, and the lapse of 

 time, have left the types so dilapidated and faded, that they no longer 

 agreed with the original description, nor gave even a tangible clue to 

 their appearance in life. 



It is not to be wondered at, therefore, that so much diversity of 

 opinion has existed and still does exist, among writers, as to the number 

 of species there really is at the present day, or that the synonymy 



