THE SKULL. 



319 



The caudal vertebrae number sixteen to eighteen ; thej' are 

 reduced to little bony cylinders. No closed neural canal runs 

 down them after the third or fourth vertebra. 



The skull or cranium (fig. 185), which articulates with the 

 axis by two bony projections, the two occipital condyles 

 (00), is divided into two regions, the cranial and facial. 

 The former is a bony box which contains the brain. The 



Fig. ISb. — Skull of the Horse. 



OC, Occipital condyle ; ST, styloid process ; OT, occipital tuberosity ; P, parietal 

 bone ; AH, auditory region ; Z, zygomatic process of temporal bone ; F, frontal bone ; 

 0, orbit ; L, lachrymal bone ; M, malar ; N, nasal bone ; SM, supra-maxillary ; OF, 

 infraorbital foramen ; FM, premaxillary ; IT, incisor teeth ; MT, molar teeth ; IM 

 inferior maxillary ; CF, eoronoid ijrocess, 



facial part constitutes the largest area of the skull. The 

 skull, which is an elongated pyramidal box in the horse, is 

 built up of a great number of bones (fig. 185). Only a few 

 of the more important can be mentioned here ; for further 

 details the reader must consult various works on osteology 

 and veterinary anatomy. 



The cranium is surrounded by flat bones at the back : these 



