IV. VERTEBRATA: REPTILIA. 



523 



responding bones of the opposite side ])y a double symphysis. In the 

 shoulder girdle scapula and coracoid alone are constant, a clavicle occur- 



MD 



t-MD 



Fig. 573. — ^Viscera of Alligator (from Wiedersheim). ED, rectum; H, heart; L, 

 liver; Lj, lung; M, stomach; AID, intestine; Oe, oesophagus; P, pylorus; Tr, trachea; 

 ZB, body of hyoid; ZH, its comua; *, perforations of hyoid. 



ring in turtles and lizards, in the latter an episternum (fig. 521) as well. 

 Of considerable systematic importance is the position of the ankle joint. 



