266 



CLASS AMPHIBIA. 



and continuous. In the higher Urodela (most Salamandridae) 

 the vertebrae are opisthocoelous. In the Anura they are usually 

 procoelous, though occasionally opisthocoelous and the noto- 

 chord is for the most part obliterated. 



-R 



FIG. 144. Longitudinal sections through the vertebral columns of some Urodeles (after 

 Wiedersheim) . A Ranidens, B Amblystoma, C Spelerpes, D Salamandrina. I, II, III, the 

 three anterior vertebrae ; Ch notochord ; Ck intravertebral cartilage ; Gp, Gk articulating 

 cup and ball ; Jvk intervertebral cartilage ; K bone of centrum ; Ligt intervertebral 

 ligament ; Mh marrow cavity ; R transverse process ; (S vertebral constriction of ihe 

 notochord ; ** the intervertebral cartilage. 



