294 



ZOOLOGY 



SECT 



blance of the pelvis of the lower Urodela, and especially of Nectums, 

 to that of Polyptems (p. 225) and of the Dipnoi (p. 243) is note- 

 worthy. In Anura the pelvic girdle resembles that of the Frog. 

 Attached to the anterior border of the pubic region there occurs 

 A in many Urodela 



and in Xenopus a 

 rod of cartilage, 

 .forked in front, 

 the epipubis (Ep). 

 It is developed in- 

 dependently of the 

 pelvis, and its re- 

 lations to that 

 structure are very 

 similar to those of 

 the sternum to the 

 shoulder-girdle ; it 

 has, in fact, been 

 proposed to call it 

 a pelvi-sternum. 



The limbs of 

 Urodela differ 

 from the typical 

 structure already 

 described only in 

 details : there are 

 usually four digits 

 in the fore-limb 

 and five in the 

 hind-limb. In 

 Anura the limbs 

 are modified by 

 the fusion of the 

 radius and ulna 

 and of the tibia 

 and fibula, and by 

 the great elonga- 

 tion of the two 

 proximal tarsals. 

 A pre-hallux is fre- 

 quently present. 



Myology. In 



the lower Urodela the muscles of the trunk and tail occur in the 

 form of typical myomeres like those of Fishes. In the higher forms 

 the myomeres become converted into longitudinal dorsal bands the 

 extensors of the back, paired ventral bands the recti abdominis, 

 and a double layer of oblique muscles, covering the flanks. 



FIG. 962. A, right side of shoulder-girdle of Salamandra ; B, 

 shoulder-girdle and sternum of Ambly stoma (Axolotl) from 

 the ventral aspect, a, b, processes of scapula ; C. (in B), 

 coracpid : Cl. procoracoid; Co. (in A), coracoid ; G. (in A), 

 glenoid cavity ; L, its cartilaginous edge ; Pf (in B), glenoitl 

 cavity ; S. scapula ; SS. supra-scapula ; st. sternum ; *, t- 

 nerve foramina. (From Wiedersheim's Comparative 

 Anatomy.) 



