40 



( ( .M 1'AILVTIVE AXATOM V. 



periphery occurs in these cartilaginous parts: in the interior of 

 each an articular cavity is formed, so that in the vertebrae of tin- 

 ner Urodeles (Salamandrina perspicillata and certain Tritons) 

 an anterior convexity a ad a posterior concavity may be distin- 

 guished, buth covered with cartilage ; they are, therefore, 

 opisthoccelous. A glance at Fig. 31,' A to D, will make this clear. 



l'\f.. ".I. L<iNf;nri>l\ \l, Si,< ilnx TIIIIOM.I' 'ilir. VERTEBRAL COLUMN OF VAEIOTT8 



URODBLES. A. RarwSon sibcricus ; I'., Awtblystoma tigrinum ; (', 



, (tin- i!nv,. iimM anterior vertebrae, /. 11, III) ; I', 

 picillata. 



I'll, jKitncliMi-d ; ./(/'. iliti-rvrrti-l.i-;il cal ! i l:i.i,'i- : <'l\~, Vi-rtcl)r:il cai t il:i;,'.' and I'ul-rclls : 

 K, ]>iTij>liiT:il luiiiy rdvi-riii'^ nf ci-iitnini ; /.', fil>s and tnm*vrrsi- jirm'i !-; ; ,V, 

 vertebral constricnon nf imtin'iiorcl in Awblystoma tigrinum, \viihiuit rartila^c 



and fat-crlls ; **, int. r\ ei \> lual rarlila.uiiicuis tracts ; M/i, Mli, marrow ca\ i 

 i.'ji, <!!.-, articular SOckel ami lirad ; J.i'jt, intci viTtd.ra] li-aim nts. 



In the drvflujuni'iit <>f the vrrtcliral column then of Urodi !< 's 

 \\- can distinguish three stages: (1) A connection of the indi- 

 vidual vertebrae by means of the intervertebraUy expanded 

 notoohord; (2) a connection by means of inier\ertebra! masses of 

 cartilage; and finally ('.\) an arlicular connect ion. These three 



