CRANIUM 183 



forms that part of the body termed the croup, and is fixed like a wedge 

 between tlie doi'sal spines of the ossa innominata or hip bones. 



The Coccygeal Vertebrae, or tail-bones, are from fourteen to 

 eighteen in number. The first three or four partake very much of the 

 character of true vertebrae, being wanting only in the oblique processes. 

 In the remainder of the tail-bones the proper vertebral characters gradually 

 become more and more obscure until they altogether disappear. 



Most of the bones of the spine present some peculiarity of form by 

 which they may be distinguished one from another; but enough has been 

 said to give the reader a general idea of their characters. 



SKULL 



The skull or bony framework of the head is situated at the anterior 

 extremity of the vertebral column, from which it is suspended by ligaments 

 and muscles, and on which it is capable of being freely moved in all 

 directions. It forms a number of cavities for the lodgment of important 

 organs, as the cranium, the orbit, and the mouth. 



In the young animal it is made up of thirty-two pieces or separate 

 l)ones, all of which, excepting the lower jaw and the hyoid or tongue 

 bone, become united in the adult by ossification. Of the thirty-two bones, 

 the following six are single: — 



Occipital Bone. Ethmoid Bone. Inferior Mca.xillaiy Bone or 



Sphenoid Bone. Vomer. Lower Jaw. 



Hyoid or Tongue Bone. 



The rest are in pairs : 



Parietal Bones. Anterior Maxillary Bones. 



Frontal Bones. Malar Bones. 



Squamous Temporal Bones. Lachrymal Bones. 



Petrous Temporal Bones. Palatine Bones. 



Nasal Bones. Pterygoid Bones. 



Superior Maxillary Bones. Turbinated Bones (two pairs). 



The head is divided into the cranium and the face. 



CRANIUM 



As compared with the body, the cranium or brain-case of the horse 

 is remarkable for its small size. (_)f the thirty-two bones forming the 

 skull, fourteen are engaged in enclosing the cranium, of which four are 

 single bones, and the rest pairs. 



