638 



REPTILIA. 



membrane bones dentary, splenial, coronoid, angular, and sur- 

 angular. 



The hyoid region is very simple. 



The pectoral arch includes a dorsal scapula and a ventral coracoid 

 (with a characteristic foramen) ; there are no clavicles; the epicoracoids 

 are thin strips between the ventral ends of the coracoids and the front 

 of the sternum ; there is an episternum ; the fore-limb is well though 

 not strongly developed ; there are five digits, webbed and clawed. 



In the pelvic arch, large ilia are united to the strong ribs of the two 

 sacral vertebrae : the pubes, or more strictly the epipubes, slope for- 

 ward and inward, and have a cartilaginous symphysis ; the ischia slope 



FIG. 351. Pectoral girdle of crocodile. 



sc,, Scapula; gl.c. t glenoid cavity; c0., coracoid; c.f., coracoid 

 foramen ; i.cl., episternum. 



backward and have a symphysis ; ilia and ischia form almost the whole 

 of the acetabulum, a small part being occupied by the true pubes. The 

 Jiind -limbs Dear f ur digits, webbed and clawed. 



Organs of Crocodilians. The Crocodilians are seen to best 

 advantage in the water, swimming by powerful tail-strokes. The limbs 

 are too weak for very effective locomotion on land, the body drags 

 on the ground, and the animals are stiff-necked. Although many, 

 especially in their youth, feed on fishes and small animals, the larger 

 forms lurk by the edge of the water, lying in wait for mammals of 

 considerable size. These they grasp in their extremely powerful jaws, 

 and drown by holding them under water. If the dead booty cannot 

 be readily torn, it is often buried and left until it begins to rot. In 

 connection with their way of feeding, we should notice several 

 peculiarities of structure ; the nostrils are at the upper end of the 

 snout, and the eyes and ears are also near the upper surface, so that 

 the Crocodilians can breathe, see, and hear while the body is alto- 

 gether immersed except the upper surface of the head ; the nostrils can 



