582 land mammals in the western hemisphere 



Suborder Anthropoidea. Monkeys, Apes, Man 



The specifically human characters will be omitted in defin- 

 ing the suborder. The Anthropoidea are plantigrade, usually 

 arboreal and pentadactyl, with opposable thumb and great toe 

 and thus the pes is hke a hand, hence the term ' ' Quadrumana " 

 formerly given to the apes and monkeys. Except in the South 

 American marmosets (Hapalidae) all of the digits have nails. 

 The canines are generally more or less tusk-like, projecting 

 above (or below) the level of the other teeth ; the premolars 

 mostly have two tubercles, like the human bicuspids, the upper 

 molars have three, or more commonly four, cusps and the lower, 

 four or five. Save in the baboons, the skull has a very short 

 muzzle and a very large cranium, the capacity of which is 

 relatively greatest in the large apes ; the brain is large and com- 

 plexly convoluted. The orbits present directly forward and 

 are deep, funnel-shaped cavities for the lodgment of the eye- 

 balls, a thin bony wall completely enclosing them externally 

 and posteriorly. The lachrymal bone and its foramen are 

 within the edge of the orbit ; the nasal bones are .short and 

 have a nearly vertical position. The two frontal bones are 

 early fused into one and usually there is no sagittal crest ; 

 the two halves of the lower jaw are coossified at the symphysis. 

 The tail is extremely variable in length and may be three 

 times as long as the body, or entirely absent. The fore and 

 hind legs are sometimes of nearly equal length, but far more 

 frequently the anterior pair are much the longer. The length 

 of the legs in proportion to that of the body is very different 

 in the different families. The humerus is much like that of 

 Man and has no epicondylar foramen ; the radius has a very 

 complete movement of rotation ; the femur never has the third 

 trochanter and the lower leg bones are always separate. The 

 thumb is more or less opposable to the other digits, except in 

 the marmosets, but never so perfectly as in Man ; the great 

 toe is also opposable, but shorter than the other digits. 



