34 ANIMAL PHYSIOLOGY. 



head of which, lying between the calcaneum and scaphoid, 

 is retained in position by a strong inferior calcaneo-scaphoid 

 ligament, which has frequently to bear nearly the whole 

 weight of the body. The outer arch is continued forwards 

 from the calcaneum to the cuboid and two outer toes, and is 

 prevented from falling flat by strong calcaneo-cuboid or 

 plantar ligaments. 



Fig, 15. SECTION OF FOOT, showing, a, the inferior calcaneo- 

 scaphoid ligament supporting the head of the astralagus. 



17. The first and second cervical vertebrae are termed the 

 atlas and axis, and are specially modified to facilitate move- 

 ments of the head, which rests on them. The atlas, instead 

 of presenting a body in front and an arch behind, has the 



Fig. 16. ATLAS AND Axis. A, Upper surface of atlas; above is 

 the ring for the spinal cord, and, separated from it by the trans- 

 verse ligament, is the ring for the odontoid process below : to 

 the sides of this are the surfaces which articulate with the skull. 

 B, Front view of the axis, with the arch seen in perspective 

 behind the odontoid process. 



hollow of its arch prolonged forwards, between the articular 

 portions which carry the skull ; and in the recent state, the 

 anterior part of this hollow is converted into a separate ring 

 by a transverse ligament. Through this anterior ring pro- 



