424 



MANUAL OF ELEMENTARY ZOOLOGY 



process which encloses a space. The first vertebra, known as 

 the atlas, is ring-shaped, with a very large vertebral foramen 

 and no centrum. The ring is divided by a ligament into an 

 upper part, through which the spinal cord passes, and a 



^Sv ,.71.8. 



Fig. 310. — Vertebra of a rabbit. 



A, Atlas, from above; B> axis, from the right; C, one of the middle cervical 

 vertebrae, from in front ; D, t fourth thoracic vertebra, from the right ; £, second 

 lumbar vertebra, from the right ; J? t the same from in front. 



a/>$., Anapophysis ; az., prezygapophysis ; cw., centrum ; <\>\, cervical rib; ep. t 

 epiphysis \f. t facet on axis for articulation with atlas :/*'., corresponding facet 

 on atlas ;_/"., facet on atlas for odontoid process; f.c./f.c'. t demi-facets for 

 heads of ribs;./!*., facets for tuberculum ; hfis., hypapophysis ; m^s., meta- 

 pophysis ; n.a, t neural arch ; n.s., neural spine ; od.p. t odontoid process ; >z., 

 postzygapophysis ; tr. t transverse process; v.c, vertebral foramen; ver,c, 

 foramen of transverse process. 



