BETWEEN TYPICAL HEPTILES AKD OTHEU ANIMALS. 191 



Lizards in wanting au episteruum and clavicles, as well as in the 

 forms of the coracoids and tlie scapulae. The shapes of the pectoral 

 bones are points in which the different Lizards differ greatly among 

 themselves- — the Skink having the episternnm + -shaped, with 

 expanded clavicles. In Monitor the scapula adjoins the coracoid 

 along its whole length ; in TJromastix the scapula has no acro- 

 mion process ; in Stellio the clavicles are brought down to the 

 anterior mai'gin of the sternum ; and in the Dragon the scapula 

 is like that of the Crocodile. 



The humerus similarly has a compressed proximal articulation ; 

 but the bone in Lizards puts on many other characters not seen 

 in Crocodiles, such as the twist in the bone, the widening of the 

 distal end, the development of the distal condyles, the thickening 

 of the radial crest, and the formation of an ulnar tuberosity. With 

 a general resemblance, the ulna has scarcely a Crocodilian charac- 

 ter beyond a compression of the bone from side to side ; for though 

 the inner outline of the bone in Lizards is concave, its outer out- 

 line is straight, and not convex as in Crocodiles, so that the prox- 

 imal end of the bone in Lizards becomes more massive, is more 

 prolonged on the outer side, and a concave articulation is made in it 

 for the humerus. 



The radius has a straight Crocodilian cylindrical shaft, but de- 

 velops characters of its own in the concave proximal end, and in 

 the process of the distal articulation, which, like that of the 

 mammalian tibia, is directed inward. 



The carpus is very unlike ; but the metacarpals and phalanges 

 differ but little. 



There are no Crocodilian characters in the pelvis. 



The Lizard femur is less unlike the Crocodile than the hume- 

 ^'us, being similar in proportion, and having a similarly compressed 

 articular head ; but while in Crocodiles the articular head is so 

 directed as to give a convex outline to the hinder side of the 

 proximal end of the bone, in Lizards the corresponding surface 

 is concave ; and the tuberosity, which on the inner side of the 

 shaft in Crocodiles is scarcely a prominence, in Lizards becomes 

 the large inner trochanter, which is especially prominent in Skinks, 

 and but slightly prominent in the Dragon. 



There is much resemblance in the proportions of the tibia and 

 the fibula : but in Lizards the distal end of the tibia sends a pro- 

 cess downward and inward as in mammals, and the proximal end 

 of the bone is compressed on the inside ; in Lizards the fibula is 



