276 PHILOSOPHY OF ZOOLOGY. 



single. The females are ovipai'ous. The species ai"e inlia^ 

 bitants of fresh waters. 



Some of the teeth in the lower jaw produced, and re- 

 ceived into a cavity in the upper. Feet half webbed, and 

 not denticulated. 



17. Alligator. Snout broad and blunt. Teeth un- 

 equal, the fourth on each side of the lower jaw produced. 

 Crocodilus sclerops. 



The produced teeth not received into a cavity in the 

 upper jaw, but pasdng along the sides. Feet webbed and 

 denticulated. 



18. Crocodilus. Crocodile. Snout oblong and flat. 

 Teeth unequal. Lacerta crocodilus, Lin. 



19- Gaviala. Gavial. Snout produced and rounded. 

 Teeth nearly equal. Lacerta Gangetica. Phil. Trans. 

 1766, p. 639, tab. xix. 



2. All the toes free. 



(a.) Tail tapering, distinct from the body. Legs de^ 

 veloped. 



With lateral expansions for flight. 



20. Draco. Dragon. On each side of the body there is 

 a membranaceous wing, scarcely connected with the legs. 

 It is supported by the first six false ribs, which, instead of 

 being bent round towards the belly for the protection of 

 the viscera, proceed laterally from the body. With this 

 substitute for a wing, the animal is assisted in its leaps 

 from one tree to another. There is a long throat-pouch 

 and lateral short ones, supported by productions of the os 

 hyoides. The teeth are of three kinds in each jaw, — four 

 incisors, two tusks, and twelve grinders. Three species 

 have been determined. 



