634 REPTILES AND AMPHIBIANS. 
very act of swallowing one about half his own size. Ihave subsequently 
seen snakes in the stomachs of other snakes, salamanders in other sala- 
manders, and it may be an interesting question as to how far this canni- 
balistic habit obtains throughout the animal kingdom. 
In the stomach of this same species, Allen* found a Chrysemis picta or 
Painted Tortoise, one and a half inches long, and saw it seize a cedar 
bird which he had shot, and which the frog proceeded to swallow, 
although the wings and tail projected from its: mouth, and there it sat 
waiting quietly for the lower end to digest. The same gentlemen, as 
well as Dr. Brewer,f states that they have seen it swallow young ducks, 
and it is a common belief of Massachusetts farmers that it robs them of 
their young chickens. The story by Dr. Jonest of finding a grass snake 
in the stomach of a large bull frog is so remarkable that we may reason- 
ably hesitate about accepting it until confirmed by other observers. 
Other frogs probably use similar food; in fact, the writer has observed 
the Rana halecina or Leopard Frog in the act of swallowing its own 
Species, and has found the elytra of beetles in their stomachs. And as 
these animals, as well as toads, lizards, salamanders, and some snakes 
subsist chiefly upon insects, they aid in keeping down the multiplicity 
of these pests, and are thus beneficial. 
The tadpoles or young of frogs, and probably also of salamanders live 
almost, or entirely, upon vegetable matter. However, in some cases they 
are said to have eaten decomposing animal matter, and even other tad- 
poles. Prof. Baird states that this may be taken advantage of to clean 
skeletons by placing the two together in water. The larval Rana sylvatica 
he found to be the most effective, as these devoured the macerated flesh, 
leaving a ligamentous skeleton. Their food primarily is vegetable, and 
it is probable that they never attack their own species unless driven by 
hunger or after they have attained a good degree of development. 
The frog is, usually at least, very cautious in regard to its method of 
taking food. It ordinarily approaches and first touches the prey with 
its tongue, then retires and afterwards returning with a spring, seizes, 
holds, and manipulates it dextrously with the fingers of its anterior feet, 
then closes its eyes, and forces the animal head foremost downwards into 
the stomach. During this operation, if interrupted, it jerks and kicks 
vigorously so long as the intruder continues its annoyance. 
The toad is a voracious feeder. It has been observed to eat nine wasps, 
one after the other, but would take no more. The same afternoon it 
* Proc. Boston Soc. Nat. Hist., Vol. 12, pp. 185-197. 
tProc. Boston Soc. Nat. Hist., Vol. 5, p. 211. 
t Chemical and Physical Investigations, Smithsonian Contributions, Vol. 8. 
