566 



AMPHIBIA. 



The skeleton of the fore-limb consists of an upper arm 

 or humerus, a fore-arm in which the inner radius and the 



FIG. 275. Pectoral girdle of Rctna esmlenta. 

 After Ecker. 



The cartilaginous parts are dotted. Ep--, Episternum ; 0111., omo- 

 sternum ; Ep.c., epicoracoids ; s/., sternum; jr., xiphisternum ; 

 c/., clavicle with underlying precoracoid cartilage; co., cora- 

 coid ; Sc. , scapula; S.sc., supra-scapula ; Gl. , glenoid cavity 

 for humerus. 



outer ulna are fused, a wrist or carpus including two 

 proximal and three distal elements, and a central piece 

 wedged in between them, five metacarpal bones, of which 



FIG. 276. Side view of frog's pelvis. After Ecker. 

 //., Ilium; Is., ischium ; Pb,, pubis ; Ac., acetabulum. 



the first corresponding to the absent thumb is very 

 small, and four fingers, of which the two innermost have 

 two joints or phalanges, while the two others have three. 

 The pelvic girdle is shaped like a V, or like a pair of 



