THE SKELETON 



o 



The cranium, thus formed of numerous originally independent 

 ossifications, which may retain throughout life more or less of their 

 individuality, or be all fused together, according to the species, the 

 age, or even individual peculiarity, consists of a brain-case, or bony 

 capsule for enclosing and protecting the brain, and a face for the 

 support of the organs of sight, smell, and taste, and of those concerned 

 in seizing and masticating the food. The brain-case articulates 

 directly with the anterior cervical vertebra, by means of a pair 

 of oval eminences, called condyles, placed on each side of the large 

 median foramen which transmits the spinal cord. It consists of a 

 basal axis, continuous serially with the axes or centra of the 



Pa 



IJP 



jcO 



Fig. 6. — Longitudinal and vertical section of the skull of a Dog (Canis famillaris), with 

 mandible and hyoid arch, an, Anterior narial aperture ; MT, maxillo-turbinal bone ; ET, ethmo- 

 turbinal ; Na, nasal ; ME, ossified portion of the mesethmoid ; CE, cribriform plate of the 

 ethmo-turbinal : Fr, frontal ; Pa, parietal ; IP, interparietal ; SO, supraoccipital ; ExO, ex- 

 occipital ; BO, basioccipital ; Per, periotic ; BS, basisphenoid ; Pt, pterygoid ; AS, ali- 

 sphenoid ; OS, orbitosphenoid ; PS, presphenoid ; PI, palatine ; VO, vomer ; Mx, maxilla ; 

 PMx, premaxilla ; sh, stylohyal ; eh, epihyal ; ch, ceratohyal ; bh, basihyal ; th, thyrohyal ; 

 s, symphysis of mandible ; cp, coronoid process ; cd, condyle ; a, angle ; id, inferior dental 

 canal. The mandible is displaced downwards, to show its entire form ; the * indicates the 

 part of the cranium to which the condyle is articulated. 1 



vertebra?, and of an arch above, roofing over and enclosing the 

 cavity which contains the cephalic portion of the central nervous 

 system (see Fig. 6). The base with its arch is composed of three 

 segments placed one before the other, each of which is comparable 

 to a vertebra with a greatly expanded neural arch. The hinder or 



1 This and many of the following figures in this chapter are taken from Flower's 

 Osteology of the Mammalia. 



