CLA88IFIGATI0N OF BATBAVHIANS. 487 



gives out an irritant acrid fluid from the ikin, which may 

 poison the eyelids. In New England toads begin to make 

 their peculiar low trilling notes from the middle to the 20th 

 of April ; from the latter date until the first of June they 

 lay their eggs in long double strings, and the tadpoles (Fig. 

 434) are usually hatched in about ten days after the eggs are 

 deposited. (Putnam.) 



The paradoxical frog of South America {Pseudes para- 

 doxa Wagler, Fig. 437, 1, 2, the larva) is remarkable from the 

 fact that the larva is larger than the adult. 3 and 4 repre- 

 sent another species of Pseudes (P. minuta). 



The highest genus of the Anura is Rana, of which there 

 are numerous species, our American forms being the bull- 

 frog {Rana pipiens Linn. ), the Rana palustris Le Conte, or 

 pickerel -frog, and the marsli-frog [Rana lialecina Kalm). 

 They lay their eggs in masses in the water in April, May, 

 and the early part of June, according to the latitude. 



While most frogs are eaten by birds, and such species are 

 preserved from extinction by their nocturnal habits and their 

 protective resemblance to the herbage and the bark and leaves 

 of trees, Thomas Belt records the case of a little Nicaraguan 

 frog which is very abundant in damp woods, and " hops 

 about in the daytime, dressed in a bright livery of red and 

 blue." Its immunity from destruction is due to the fact 

 that ducks and fowl could not be induced to eat it, owing to 

 its unpleasant taste, the same reason inducing birds to reject 

 certain bright-colored caterpillars, which are distasteful to 

 them. 



Class V,— BATRACHIA. 



Amphibious Vertebrates, with gills in certain adult aquatic forms, all 

 breathing air by lungs ; the skin of existing species naked ; with true 

 limbs like those of higher Vertebrates ; skull vyith two occipital condyles ; 

 heart with two auricles and one ventricle. Mostly oviparous; a distinct 

 metamorphosis. 



Order 1. Trachystomata. — Body long, eel-like, with persistent gills ; 

 no pelvic bones or hind limbs ; no maxillary bone. (Siren.) 



