2l6 



ELEMENTAR Y ANA TOMY. 



[LESS. 



exceptional structure, the odontoid process of the axis verte- 

 bra of man. 



3. First, as to the question just suggested regarding man's 

 cervical vertebrae. 



It is well known to anthropotomists that the ventral 

 (anterior) root of the transverse process of the seventh cer- 

 vical vertebra (if not also of vertebrae nearer the head) ossi- 

 fies separately. 



At the same time the dorsal (posterior) root of the same 

 transverse process plainly answers to the whole of the 

 so-called transverse process of a dorsal 

 vertebra, namely, to that part which 

 articulates with the tubercle of the rib. 

 As we have seen, this cervical trans- 

 verse process may be, in the lowest 

 Mammals and in Crocodiles, a distinct, 

 more or less Y-shaped bone. 



Now, just such a condition of the 

 proximal end of a rib is, as we have seen, 

 well exemplified in many Batrachians 

 (e.g. Menopoma and Menobranchus], in 

 which a dorsal (tubercular) and a ventral 

 (capitular) transverse process articulate 

 with a Y-shaped rib, one branch being applied to each process. 

 Thus a Y-shaped bone attached to a cervical vertebra may 

 be interpreted in two ways : (i) as a small rib which has united 

 with it parts of both the " tubercular " and the " capitular " 

 processes of the vertebra to which it is annexed ; or (2) as 

 a rib with a " tubercle " so largely developed as to equal the 

 "head and neck" in size. 



Plainly, then, the "perforated" transverse processes of 

 man's cervical vertebrae consist, in part, of rudimentary ribs. 



FIG. 184. Vertebras of 

 an Axolotl, showing 

 the proximal bifurca- 

 tion of the rib to meet 

 the superimposed par- 

 axial processes ; d, tu- 

 bercular process ; p, 

 capitular process ; s t 

 spinous process. 



Frc. 185. -LATERAL VIEW OF SIXTH VERTEBRA OF SALAMANDRA. 



This figure shows the rib bifurcating not only proximally to meet the super-imposed 



paraxial processes, / and c (diapophysis and parapophysis), but also distally. 



It was noted that the distal ends of the cervical transverse 

 processes of man diverge as two small processes, termed 



