Fig. 13.—Hind and Fore Limbs of Xenopus.
B. The Vertebral Column.
1. Remove the skin and muscles from the dorsal surface of the back to show the nine vertebræ and the urostyle. Make a drawing showing the vertebræ with their transverse processes, and the urostyle attached to the posterior end of the 9th vertebra.
Fig. 14.—Vertebral Column of Xenopus and Rana.
The 2nd, 3rd and 4th vertebræ 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 vertebræ 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.