310 VERTEBRATES: BATRACHIANS. 



feed upon vegetable food. As they grow older, the ex- 

 tremities appear, the tail is gradually absorbed, the gills 

 are superseded by lungs, and the animal becomes air- 

 breathing and carnivorous. This Order comprises three 

 families, Ranidse or Frog Family, Hyloidae or Tree- 

 Toad Family, and Bufonidas or Toad Family. 



RANID.E, OR FROG FAMILY. This Family comprises 

 tailless batrachians which have the fingers and toes free, 

 and never dilated into a disk, tympanum visible, upper 

 jaw and palate provided with teeth, and the throat of the 

 males with vocal vesicles, which communicate internally 

 with the mouth. The genera and species are numerous. 



The Genus Rana comprises the Frogs proper. 



The Bull-frog, R. Catcsbiana, Shaw, R. pipicns, Latr., 

 of the United States, attains a total length of twenty-one 

 inches, in some instances. It is mainly solitary, and is 

 the most aquatic of all the frogs. The deep croakings of 

 the male may be heard a mile. R. horiconcnsis, Holbr., 

 of Lake George, is a closely related species. 



The Green Frog, R. clamitans, ~Rosc.,R.fontanalis, LeC., 

 of the United States, is three and a half inches long, 

 green above, with dusky spots behind, tinged with yellow 

 below. There is a ridge from the orbit to the posterior 

 extremities. 



The Leopard Frog, 



Fig. 166. 



R. halecina, Kalm, of 

 North America, is 

 over three inches long, 

 green above, with 

 spots of dark brown 

 margined with yel- 

 low ; beneath yellow- 

 ish white. This beau- 

 tiful frog is very ac- 



times eight or ten feet at a single bound. 



