SKELETON pi 



an inierveriebral foramen which permits the pas- 

 sage of blood-vessels and nerves to and from the 

 neural canal. 



1. The Cervical Vertebrae form the skeleton of the 

 neck. The most anterior cervical vertebra, the 

 atlas, is somewhat modified to support the skull. 

 It bears on its anterior side two concave articular 

 surfaces which receive the condyles of the skull. 

 Its transverse processes form two wing-like ex- 

 pansions. (Plate I., D.) The second cervical ver- 

 tebra, the axis, is also modified. It bears at its 

 anterior end a pivot, the odontoid process, on which 

 the atlas turns. The odontoid process is mor- 

 phologically the body of the atlas. (Plate I., e.} 

 Each of the six anterior cervical vertebrae are 

 pierced by two foramina, one on either side of the 

 neural canal. 



2. The Dorsal Vertebrae are characterized by the 

 great development of their posteriorly-directed neu- 

 ral processes, and by the costal facets. (Plate I., g.) 



3. The Lumbar Vertebrae are larger, with well-de- 

 veloped transverse processes and anteriorly-directed 

 neural processes. (Plate I., h.) 



4. The Sacral Vertebrae are more or less com- 

 pletely united together and serve for the attach- 

 ment of the pelvis. 



5. The Caudal Vertebrae gradually become smaller 

 and their processes reduced. Certain of the cau- 

 dal vertebrae bear beneath their anterior ventral 

 surface small chevron bones. (Plate I., i.) 



