BONES OF THE HEAD. 191 



23, 23. The pastern of the hind feet, including the upper and 

 larger bone, (fig. 23,) the lower pasteyn, (fig. 25,) and 

 the coffin-bone, (fig. 24.) 



26, 20. The caudal vertebras, or bones of the tail. 



BONES OF THE HEAD. 



PLATE YIII. Fig. 2 and 3. 



The head contains the brain and other important organs 

 of sense. It is divided bv anatomists into two parts, 

 namely, the skull and the face. The skull, or cranium, 

 is that portion in which the brain is situate ; and the bones 

 in which it is enveloped are destined for its protection. 

 This division consists of nine bones : the two frontal bones, 

 a, a; two parietal, c, c; two temporal, d, d; the occipital, 

 g ; the ethmoid ; and sphenoid : the two latter are situate 

 at the base of the skull, and are not visible in a front view, 

 but their position will be seen in fig. 3, plate iii., the 

 ethmoid, or sieve-like bone, immediately above k, and 

 sphenoid, I. These nine bones are separated in the foal 

 at an early period of its existence ; but soon after birth 

 they are firmly united together by the sutures, at which 

 parts they are so strong that fracture seldom or never occurs 

 there. 



There is a beautiful evidence of design in this division 

 of the head into so many bones. When the foetus of the 

 foal in the womb first assumes a form, and may be said 

 to be in life, this portion of the skull is merely a jelly-like 

 consistence, which is gradually changed into a harder sub- 

 stance, called cartilage ; and previous to the birth of the 

 animal much of this cartilaginous substance is carried ofi 

 by certain vessels emanating from the brain, called ab- 

 sorbents, and bone is deposited in its stead. In all the 

 flat bones, such as those of the head, this deposit takes 



