382 VERTEBRATE ZOOLOGY 



rived from a common ancestral stock. Doubtless, were we to discover 

 this common ancestor, we should be inclined to call it an ape, but 

 it certainly was not very much like any of the present-day apes. 



The family may be defined as follows: tail rudimentary as in Man; 

 no cheek pouches; no ischial callosities except in the gibbon; arms 

 longer than legs; the great toe fully opposable; the shoulders broad; 

 bipedal habits; always a vermiform appendix; hair mainly on the 

 ventral side of the body and on the limbs. The number of species is 

 not great and there is so general an interest in them that we may 

 spare the space to give a brief description of the principal ones. 



The gibbon (Fig. 194, D), Hylobates, is a rather small ape with 

 exceedingly long arms, that touch the ground when it stands erect. 

 It has small rump callosities similar to those of the baboons. Its 

 dentition is adapted for a fruit-eating habit, though the canines are 

 large and saber-like for self-defense. The skull is rounded and with- 

 out the sagittal crest characteristic of the gorilla. It has a very 

 erect posture both in walking and in sitting, the head being set upon 

 the neck much as in Man. The gibbon has a tremendous voice, much 

 more voluminous than that of Caruso, though it weighs not more 

 than about sixty pounds. It lives in heavily wooded mountain slopes, 

 remaining largely in 'the trees, through which it is capable of 

 making wonderful speed. With its long arms it swings along 

 with a hand-stride of twenty to forty feet, and never misses a hold, 

 though it must calculate the distances with great nicety or fall 

 from great heights to the ground. Any animal that can use its arms 

 and hands in this way must have a finely developed brain back of it; 

 indeed the gibbon's brain development is exceptional, especially in 

 the visual and tactual centers. When walking on the ground the 

 gibbon walks erectly but very awkwardly, balancing itself by touch- 

 ing the knuckles of the hands to the ground. It is evidently about 

 nine-tenths an arboreal creature, using the ground only when trees 

 are not available. 



The orang (Fig. 195), Simia satynts, is a large ape native to 

 Sumatra and Borneo. It is short and stocky, and has reddish hair. 

 Though it is only about four feet in height it has an arm-spread of 

 over seven feet. The head is short and broad and the eyes very close 

 together. The skull has a sagittal crest for the attachment of the 

 powerful neck muscles; the jaw is deep and massive and is used both 

 for tearing open fruits and in fighting. The hands are the chief 



