ELEMENTARY ANA TO MY. 



[LESS. 



pass out through perforations in the neural arches them- 

 selves, and not between the notches of contiguous arches. 



There may be additional parts and processes which are 

 quite wanting in man, except as represented by the slight 

 median ridge in front of the axis vertebra. 



Such are the processes (sometimes median and azygos, 1 

 sometimes paired) which appear on the ventral aspect of the 

 centrum in many animals, and which are termed hypapo- 

 physes. 2 They may exist as single processes, as in the Hare 

 and in poisonous Serpents, which have them developed 



FIG. 54 ANTERIOR SURFACE OF THE 

 LUMBAR VERTEBRA OF HARE (Lejus 

 timidus). 



FIG. 55. ANTERIOR SURFACE OF 

 TWELFTH CAUDAL VERTEBRA 

 OF LEOPARD. 



in, metapophysis ; /, processes 

 serially continuous with those 

 which support the posterior 

 zygapophyses in the anterior 

 vertebra ; h, hypapophyses. The 

 process on the side of the body 

 between m and h is the anterior 

 transverse process. 

 (From Prof. Flower's "Osteology."} 



s, spinous process ; m, metapophysis ; az, 

 anterior zygapophysis ; t, transverse 

 process ; h, hypapophysis. 

 (from Prof. Flower's " Osteology"} 



throughout the greater part of the vertebral column. In the 

 harmless snake Rachiodon some of these processes extend 

 into the oesophagus (swallow), and becoming coated with a 

 toothlike substance, act as teeth. Hypapophyses may be 

 developed as paired processes, as in the coccygeal vertebrae 

 of many beasts, or they may be in the form of Y-shaped 

 arches, as we commonly find them beneath some or other of 

 the coccygeal vertebrae when these latter are large and 

 numerous. 



23. DORSAL VERTEBRAE, if by that be meant "vertebrae 

 bearing ribs," are constant parts in all Vertebrates, save 

 those in which, like the Lancelet and Marsipobranchs, neither 

 vertebrae nor annexed lateral and body-encircling structures 



1 Azygos, from a, not, and "?<'?> a fellow. This term is applied to parts 

 which are single, as opposed to tho-e which exist in pairs. 

 ' 2 From UTTO, under, and apophysis. 



