THE RABBIT. 263 



consisting of twelve or sometimes thirteen rib-bearing ver- 

 tebrae ; the lumbar region, containing seven or some- 

 times six large vertebrae without ribs; the sacral region, 

 consisting of four vertebrae more or less completely fused 

 into a single bone, the sacrum ; and lastly, the caudal 

 region, containing about fifteen vertebrae, which extend 

 from the sacrum to the end of the tail. 



4. The skull, consisting of the skull proper (brain-case 

 and upper jaw), the lower jaw or mandible, and the 

 tongue-bone or hyoid. 



5. The shoulder-girdle, consisting on each side of the 

 scapula, or blade-bone, and of the small clavicle, or 

 collar-bone. 



6. The hip -girdle, consisting of large paired bones, 

 the ossa innominata, united both with one another and 

 with the sacrum. 



7. The fore-limb, divisible into three parts : a proximal 

 division, consisting of a single bone, the humerus ; a 

 middle division, containing two bones, an inner, the radius, 

 and an outer, the ulna ; and a distal division, the manus, 

 made up of the carpus or wrist, and of five digits. 



8. The hind-limb, also divisible into three parts : a 

 proximal, containing a single bone, the femur ; a middle, 

 consisting of a large inner bone, the tibia, and a small 

 outer one, the fibula ; and a distal, the pes, consisting of 

 the tarsus or ankle, and of four digits. 



III. In one of the first half-dozen thoracic vertebrae 

 note : 



9. The centrum or body, a sub-trihedral mass of bone 

 forming the ventral portion of the vertebra. 



10. The neurapophyses or neural processes, paired 

 bony rods, passing upwards and slightly outwards, one from 

 each side of the centrum and uniting with one another 



