Vertebrae of Rabbit. il 



however absent in the Leporidae, though present in the Rat and 

 many or most other Rodents. The second cervical or '^ axis' 

 vertebra has its spine greatly developed, both anteroposteriorly 

 and vertically, giving- attachment by it both to the muscles which 

 move, and the elastic ligamentum nuclicie which supports the head. 

 It has no anterior articulating processes upon its neural arch in 

 mammals, but it comes into articular relation with the atlas 

 by means of two oblique zygapophysial surfaces developed on 

 either side of the base and a third on the front of its odontoid 

 process, which is the backwardly displaced and anchylosed centrum 

 of that vertebra. It is the deepest from above downwards, and 

 the longest from before backwards, but also the narrowest from 

 side to side of the cervical series. The first two cervichl vertebrae 

 articulate with each other and with the occiput by means of 

 synovial joints as the neurapophysial processes are articulated to 

 each other throughout the rest of the trunk, where however the 

 centra are connected by interarticular fibrocartilaginous discs 

 containing in their central pulp remnants of the primitive chorda 

 dorsalis. The neural spines of the third and fourth cervical 

 vertebrae are low but long, corresponding with the long neural 

 roof which these two vertebrae possess ; the spines of the shorter 

 neural arches of the fifth, sixth, and seventh vertebrae have more 

 of the shape which their name implies. The lateral processes or 

 'cervical ril)s' of these vertebrae are greatly developed; those of 

 the atlas more or less obliquely outwards, those of the axis back- 

 wards ; those of the third, fourth, fifth, and sixth, both anteriorly 

 and posteriorly, and those of the seventh outwardly. The fourth, 

 fifth, sixth, and seventh have prominent upgrowths developed on 

 .this process or rib which are homologous apparently with the 

 prominent tubercles of the ribs of these creatures, or, possibly, with 

 the metapophyses of the dorsal ribs. This process makes up by 

 itself almost the whole of the transverse process of the seventh 

 cervical vertebra, the inferior, antcroposteriorly-produced, process, 

 which is much larger in the preceding vertebrae and largest of all 

 in the one immediately preceding, being lost in this, the last of the 

 series. These inferior elements of the transverse processes, by 

 bending inwards form with the vertebral bodies furrows, in which 

 the long anterior neck muscles are lodged, a central slightly-raised 

 line marking the line of separation of these muscles and reprc- 



