SIMIAD.E. 363 



a want of development in those peculiar muscles which enable the 

 human subject to walk with ease and vigour, but the ligament (ligamen- 

 tum teres) which binds the head of the thigh-bone to the bottom of the 

 socket, is altogether wanting ; an arrangement which diminishes the 

 firmness of the joint, while, at the same time, it adds very considerably 

 to its freedom and flexibility. Thus, the short, ill-turned, and loosely- 

 jointed legs < of the Orang render its movements on the ground tottering 

 and unsteady, when, as it sometimes does, it balances itself upon them, 

 and waddles awkwardly along : in ordinary locomotion on the ground, 

 its arms are its principal agents ; these are of enormous power and 

 length ; they actually touch the ground, and serve as crutches ; for, 

 resting his weight on the bent knuckles, the Orang swings, or drags, the 

 body along, the legs performing only a secondary part in the efforts of 

 progression. Among the trees, however, this awkwardness is exchanged 

 for great activity and freedom ; there, its long arms, its hook-like hands 

 and feet, its obliquely fixed and flexible hinder limbs, and the strength 

 of its thickset shoulders, combine to its advantage. But, in the Chim- 

 panzee, its adaptive structure for arboreal habits is less in the ex- 

 treme. In the first place, its lower limbs are larger in proportion than 

 in the Orang ; and though their tournure is obliquely inward, the palms 

 of the feet, or hinder graspers, are capable of being applied fairly to the 

 ground, and the hip-joint is secured by the ligamentum teres ; whence 

 the action of the lower limbs is more firm and steady. The arms, 

 though long, reach only a little way below the knees, and both the hands 

 and feet are broad, comparatively short, and have less of that hook-like 

 character which is so remarkable in the Orang. The thumb of the 

 hand has not, it is true, the same development as in Man ; otherwise, 

 this organ nearly resembles, in form, that of the human hand ; and the 

 thumb of the foot is of considerable development ; while, in the Orang, 

 it is short, and often destitute of the terminal phalanx. With respect to 

 other external differences, it inay be observed that, in the Orang, the ears 

 are small, and lie flat on the skull ; while, in the Chimpanzee, they are 

 large, and stand out from the head. In both there is a similarity in the 

 face, which is grave, and even melancholy, especially that of the Orang ; but 

 in the Chimpanzee the cheeks are more furrowed with wrinkles than in 

 the Orang; while the muzzle, being furnished with thinly-scattered white 

 hairs, gives to the young individual a grotesque appearance of age, in 

 contrast with the playful habits of a child. In both animals the lips are 

 endowed with great mobility, and are capable of extraordinary protrusion ; 

 but the chin is larger and more prominent in the Chimpanzee than in 

 the Orang ; in which latter, this part retreats at once from the protruding 

 lips, and over these no white hairs are scattered. In the Chimpanzee 

 the hair of the head radiates from a centre, and the back of the fore- 



