180 



SUBKINGDOM VEKTEBKATA. 



At length the posterior extremities show themselves ; then 

 the anterior ; the tail is absorbed (not dropped off) ; the 

 lungs are developed; the branchiae waste away; and the 

 little animal matures into a frog. Destitute of ribs, it 

 breathes like the tortoise, by swallowing air. 



PRESENT ; TYMPANUM DISTINCT 

 UPPER JAW TOOTHED. 



PRESENT ; TYMPANUM INDISTINCT ; 

 JAWS TOOTHLESS. 



ABSENT ; TYMPANUM CONCEALED ', 

 JAWS TOOTHLESS. 



' I Ranidse, 

 Bufonidae, 

 Pipidse, 



Ranapipiens, Bull- frog. 



Bufo americana, Common Toad. 

 Pipa americana, Surinam Toad. 



Ranidae. The Common Frog (Eana pipiens) is a type 

 of this family. Living mostly in the water, the toes of 



Fig. 306. 



Ranapipiens, Bull-frog. 



its hind limbs are webbed. The Tree Frog (Hylulce) has a 

 viscid ball or sucker on each of the toes, by which it can 

 climb easily. It lays its eggs on trees which overhang the 

 water, and, when hatched, the young drop into it. In cold 

 latitudes, all the species hibernate in the mud. 



