CH. VIII] FROGS, TOADS, AND NEWTS 269 



of the hyoid. hy'. Its anterior cornu. hy". Its posterior cornu 

 (thyro-hyoid). in.f. Intervertebral foramen. m.cp. Metacarpus. 

 mx. Maxilla. na. Nasal. n.a. Neural arch. n.sp. Neural 

 spine. ph. Phalanges. p.mx. Pre-maxilla. pt. Pterygoid 

 bone. q.j. Quadrato-jugal. rd. Radius. s. Sacrum. 



sh.g. Shoulder-girdle. sp.e. Sphenethmoid. sq. Squamosal. 

 tb. Tibia. tb.p'. Tibio-tarsal joint. tr.p. Transverse process. 

 ts. Tarsus. ul. Ulna. ust. Urostyle. v.c. Vertebral 



column. vo. Vomer. zy'. Anterior zygapophysis. zy". 



Posterior zygapophysis. I to V. Digits i to v. 



tunnel. Bony outgrowths for the attachment of muscles 

 arise from the neural arches : each vertebra bears upon 

 the summit of the arch a low crest, the neural process, 

 and, with the exception of the first or atlas vertebra, a 

 pair of transverse processes, one on the right and the 

 other on the left side, at the junction of the arch with 

 the centrum. To these processes and also to the sides 

 of the urostyle numerous muscles are attached, while to 

 the stout transverse processes of the ninth vertebra are 

 firmly fastened the long ilia of the pelvic girdle. The 

 pelvic girdle connects the hind leg with the trunk, and 

 it is thus through the ilia that the movements of the legs 

 are transferred to the body as a whole, hence in leaping 

 and swimming severe strains are thrown upon the ninth 

 pair of transverse processes, and extra strength is required 

 in them. 



The head is capable of movement up and down upon 

 the atlas vertebra, the two smooth occipital condyles 

 working in corresponding concavities in the anterior face 

 of the centrum of the atlas. A limited amount of " play " 

 is permitted between the successive vertebrae by their 

 articulations one with another. The centra fit into one 

 another by ball- and socket-joints : the first seven vertebras 



