B. The Vertebral Column. 



i. Remove the skin and muscles from the dorsal surface of the back to 

 show the nine vertebra? and the urostyle. Make a drawing showing the 

 vertebras with their transverse processes, and the urostyle attached to the 

 posterior end of the 9th vertebra. 



Atlas 

 - Axis 



■Transverse process 

 Cartilaginous rib 



Transverse process 

 of 9th vertebra 



Urostyle 



.Transverse 

 process 



Transverse process 

 of 9th vertebra 



Urostyle 



Fig. 14.— Vertebral. Column of Xenopus and Rana. 



The 2nd, 3rd and 4th vertebra? bear long transverse processes curved 

 backwards, those of the 3rd and 4th being tipped with small cartilaginous 

 ribs. The transverse processes of the 5th, 6th, 7th and 8th vertebra? are 

 slender and project forwards and outwards. The 9th vertebra has long 

 flat wing-like processes attached to which are the ilia of the pelvic girdle. 

 The urostyle is fused to the 9th vertebra. 



[In the Frog the transverse processes are produced outwards and they do 

 not bear cartilaginous ribs. The urostyle is attached to the 9th vertebra by two 

 facets.] 



Note the intervertebral foramina for the exit of the ' nerves from the 

 spinal cord, and the intervertebral discs. 



32 



