4 6 



ELEMENTARY ANATOMY. 



[LESS. 



Those small and insignificant processes which make their 

 appearance as mere rudiments on the last dorsal of man are 

 commonly much larger in other Mammals, and may be 

 exceedingly developed ; as, however, they attain their maxi- 



FIG. 59. FRONT AND BACK VIEW OF A VERTEBRA OF A RATTLE-SNAKE 

 (Crotalus). 



c (in left-hand figure), concavity of pre-axial surface of centrum ; c (in right- 

 hand figure), convexity of post-axial surface of centrum ; s; neural spine ; hy, 

 hypapophysis ; 0', post-zygapophysis ; t l , tubercular process ; t 2 , capitular 

 process ; /3, peculiar extra transverse process ; za, zygantrum ; zs, zygosphene. 



mum in the lumbar region, they will be better described 

 hereafter. They are not certainly present in Vertebrates 

 below Mammals. But in some Chameleons (e.g. C. Parsonii} 



FIG. 60. SIDE VIEW OF TWELFTH AND THIRTEENTH THORACIC VERTEBR/E OF 

 GREAT h. 



m, metapophysis ; tc, facet for articulation of tubercle of rib ; cc, ditto for capitulum 

 of rib ; az t anterior zygapophysis ; az 1 , additional anterior articular facet ; 

 pz, posterior zygapophysis ; pz l and pz 2 , additional posterior articular facets. 

 (From Professor Flower s "Osteology ") 



a prominence is developed from each prozygapophysis, which 

 may be a metapophysis, and this attains a very great size in 

 some C.olubrine snakes. In Birds such a process exists, 



