598 



BEPTILIA 



[CH. 



~* Order IV. Crocodilia. 



The last and highest order of the Reptilia is the Crocodilia. 

 These animals agree with the Chelonia in having a series of osteo- 

 derms underlying the horny scales of the skin, also in having an 

 immovable quadrate and a single median copulatory organ, hut in 

 spite of these resemblances, they seem to belong to the same stock 



.& 14 



21 * 



13 



FIG. 297. Palatal aspect, A. of the cranium, B. of the mandible of an Alligator, 

 Caiman latirostris x 4j . 



1. Premaxilla. 2. Maxilla. 3. Palatine. 4. Pterygoid. 5. Posterior 

 nares. 6. Transverse bone. 7. Posterior palatine vacuity. 8. Anterior 

 palatine vacuity. 9. Basi- occipital. 10. Opening of median 



Eustachian canal. 11. Jugal. 12. Quadratojugal. 13. Quadrate. 

 14. Dentary. 15. Splenial. 16. Coronoid. 17. Supra-angular. 

 18. Angular. 19. Articular. 20. Lateral temporal fossa. 21. Openings 

 for the passage of blood-vessels supplying the alveoli of the teeth. . 



as Sauria and Uhynchocephala ; they are Diapsid not Monapsid in 

 their skulls. It must be remembered that many families of Lizards 

 possess osteoderms. 



The Crocodiles are of large size and are decidedly Lizard-like in 

 their general appearan.ce, the chief observable external difference 

 between them and the Lacertilia being in the jaws, which are 



