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 HominidcBj containing only Man him- [Case l.J 
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, 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 vertebrse. 
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 
F 2 
