xviii INTRODUCTION 



noticeable in the male, and is designed to protect and enclose the vocal 

 organs which are of very great size. 



The shape of body and the manner in which the limbs are pro- 

 portioned to it, vary to a considerable degree in these American 

 Monkeys, and it would be difficult to find a greater contrast than the 

 slender, slim-waisted body, and long, attenuated limbs of Ateleus 

 covered with smooth straight hair, and the thick-set, robust body, 

 moderately long, stout limbs, and woolly coat of Alouatta. 



The genus with the largest number of species in the New World 

 is Cebus containing the well known Capuchin Monkeys, remarkable 

 for their restless, mischievous dispositions, and the wonderful diversity 

 they exhibit in the coloring of their coats. 



No American Monkey possesses either cheek pouches or callosities, 

 nor is the external auditory meatus ever present. 



The species of the Cratarrhine group are very different in appear- 

 ance from the Monkeys of the New World. The limbs are sometimes 

 of equal length, but generally the legs are longer than the arms except 

 in the great Apes whose arms are invariably longer than the legs. The 

 thumb when present is opposable to the fingers, as is also the great 

 toe to the digits of the foot, and is always shorter than the other toes. 

 The tails vary in length from a mere knob to one exceeding the head 

 and body. Many of the species possess cheek pouches, and callosities 

 are also present in many, sometimes of large dimensions and colored 

 with the most brilliant hues. The Family Lasiopygid^;, to which 

 precedence is given in the arrangement of the Suborder, contains the 

 Baboon, Guenons, Langurs, Guerezas, etc., in fact all the Old World 

 species of ANTHROPOIDEA except the Man-like Apes of the 

 Families Pongihxe and HylobatidvE. 



The Baboons, which come first in the arrangement of the Families 

 are, besides other physical traits, characterized by an elongate muzzle, 

 which in one species at least is decorated by brilliant coloring, (P. 

 sphinx Linn.). The limbs are nearly equal, but the tails are very 

 variable in length and in the density of their hairy covering. The 

 canine teeth are very long, in some cases prodigiously so, and capable 

 of inflicting a wound as serious as that of almost any dagger. The 

 cheek pouches, in all species that have them, are constructed of folds 

 of skin which expand when food is forced into them, contracting again 

 when emptied and then giving no indication of their presence. These 

 pouches, being placed on the outer side of the jaw, are no hindrance 



