VERTEBRAL COLUMN 



43 



tissue, extend iuwards towards the centre, gradually constricting 

 the notochord so that it may eventually become entirely 

 obliterated. Finally a differentiation, as well as a resorption, 

 ■extending inwards from the periphery, occurs in these cartilaginous 

 parts : in the interior of each an articular cavity is formed, so that 

 in the vertebrae of the higher Urodeles an anterior convexity and 



ITiG. 33. — Longitudinal Section through the Vekteeral Column of ^'AKIous 

 Urodeles. A, Ranorlonsiherimx ; Ti, Amhlystoniatigrimt'in ; C, (!i/riii.ophi/ii-^ 

 jmrphyritirnfi (the three anterior vertebrai, /, //, ///) ; D, S'llnmnnilr'nui, 

 perspkillata. 



•Oh, notochord ; Jrlc, invertebral cartilage : GK, vertebral cartilage and fat-cells ; 

 K, peripheral bony covering of centrum ; R, rib.s and transverse processes ; S, 

 vertebral constriction of notochord in Amhly stoma tiyriinim, without cartilage 

 and fat -cells in this region ; **, intervertebral cartilaginous tracts; MIi, Mh, 

 narrow cavities ; G]], Gl; articular socket and head ; Lir/t, intervertebral 

 ligaments. 



-a posterior concavity may be distinguished, both covered with 

 •cartilage ; they are, therefore, opisthocmlous. A glance at Fig. 33, 

 A to D, will make this clear. 



In the development of the vertebral column of Urodeles we 

 ■can thus distinguish three stages: — fl) A connection of the indi- 



