180 



SUBKINGDOM VERTEBBATA. 



At length the posterior extremities show themselves; then 

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

 lungs are developed; the branchife 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 ; TTMPANOM INDISTINCT ; 

 JAWS TOOTHLESS. 



ABSENT ; TyMPANTJM CONCEALED ; 

 JAWS TOOTHLESS. 



\ 



I Buf< 

 (. Pipid 



RanidEE, Ranapipiens, BiiU-frog. 



fonidffi, Bufo americana, Common Toad. 

 Pipa americana, SitHnam Tood. 



Ranidae. — The Common Frog (Rana pipiens) is a ,+ype 

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



Fig. 306. 



Bana pipiens, Bull-frog. 



its hind limbs are webbed. The Tree Frog {Hylidm) 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. 



