CLASSIFICATION OF BATRAUHIANS., 487 
gives out an irritant acrid fluid from the skin, 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 marsh-frog (Rana halecina 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. 
Crass 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 with 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.} 
