SKELETON OF MAN. 67 



ankle-bones, corresponding to the carpus, and the metatarsals (m) 

 and toe-bones (ph) to the metacarpals and finger-bones. 



The digits never exceed five in number on each limb, and are 

 often less numerous, being even in some cases, as in the Horse, 

 reduced to one. 



Order I. PRIMATES. 



The Primates (see p. 6) are, in their osteological characters, 

 distinguished from other Mammals by having their orbits com- 

 pletely surrounded by a bony plate, by always having clavicles 

 or collar-bones, by the presence, with but few exceptions, of five 

 digits on each extremity, the first digit of the anterior limb, the 

 thumb or pollex, being sometimes, and that of the hind limb, 

 the great toe or hallux, being almost always freely opposable to 

 the other digits, and very largely developed. There are never 

 more than two incisors on each side of each jaw, and canines 

 are almost invariably present. 



The first Family is the Homintdtij containing only Man him- [Case 1.] 

 self (Cases 1 and 2, Div. A and B). His skeleton differs from 

 the typical Mammalian type described above mainly in relation 

 to the upright position of the body, and the total withdrawal of 

 the anterior limbs from the function of progression, and their 

 modification into grasping and tactile organs; at the same time 

 the hind limbs are developed sufficiently to be capable, by them- 

 selves, of supporting and moving the whole weight of the body. 

 The direction of the hind limbs is in a straight line with the axis 

 of the vertebral column, instead of at right angles to it 3 as in other 

 Mammals ; the pollex is so attached to the carpal bones as to be 

 completely opposable to the other four digits, while the hallux, 

 or great toe, is fixed parallel to the other toes, so that the foot 

 is quite flat beneath, with but little power of grasping, but forming 

 an admirable base on which the body may be balanced. The tail 

 is only represented by the coccyx, an immovable bone composed of 

 from three to five coalesced vertebrae. 



The skull differs from that of the other Mammals in the great 

 size of the brain-case, and the proportional reduction of the bones 

 of the face, the natural result of the high development of the 



F2 



