REPTILES. 



301 



sauridse were remarkable for a combination of reptilian with 

 cetacean types of structure, the Pterodactylida? are no less 

 so, for the singular affinities they establish between birds, 

 bats, and lizards. It includes but one genus, Pterodactylus* 

 In the length of the neck, and in the form of the head, it 

 resembles a bird. (Fig. 204.) The trunk and the tail are 

 like a quadruped. The numerous conical recurved teeth are 

 formed after the Saurian type. The anterior extremities are 

 constructed after the character of bats ; the radical finger 

 having been greatly elongated, and adapted for supporting a 

 membranous wing, by which these ancient reptiles were 

 enabled to soar through the air. "We know seventeen species 

 of this remarkable genus; one from the lias; one from the 

 great oolite ; fourteen from the Oxford stage of Solenhofen ; 

 and one from the wealden. 



6th Family. The LABYEIKTHODONTID^. Had the surface 

 of the cranial bones wrinkled. The structure of the skull 

 of this family is intermediate between the Saurians and the 

 Batrachians. The form of their jaws, with their large teeth im- 

 planted in sockets, establish an evident analogy between them 

 and the Ichthyosauridse ; whilst some anatomical points in 

 the osteology of the skull appear to connect them with the 



FIG. 205. Python tigris. 

 * See frontispiece. 



