THE SPINAL SKELETON. 



49 



Y-shaped bones ; and we find the same in the Crocodile, 

 where the free end of each Y-shaped bone is singularly pro- 



FIG 62 SECTION THROUGH MIDDLE LINE OF UNITED CERVICAL VERTEBRA 



OF GREENLAND RIGHT WHALE (Baltena mystutus). 



a articular surface for occipital condyle ; e, epiphysis on posterior end of body of 

 'seventh cervical vertebra ; sn, foramen in arch of atlas for first spinal nerve ; 

 i, arch of atlas ; 2, 3, 4, 5, 6, conjoined arches of the axis and four following 

 vertebrae ; 7, arch of seventh vertebra. 



(From Prof. Flowers "Osteology") 



lono-ed in the line of the backbone i.e. pre- and post-axially. 

 In many lizards and birds the posterior cervicals bear long 



FIG 63 Third Cervical Vertebra of a nearly full-grown Echicna (E. hystn.r), 

 the different pieces of which it is composed being slightly separated from one 

 another. tin, neural arch ; c, centrum ; t, transverse process ; v, arterial 

 canal; ncs, neuro-central suture. 



(From Prof. Flowers "Osteology") 



ribs and are only counted as cervical because their ribs do 

 not join a sternum, which yet is attained by the ribs of other 

 vertebras. 



