Since the animals herein described are a source of discomfort and 

 ahu-m to many people, it may be well to say here that of aU the ba- 

 trachians and reptiles known to inhabit Indiana, but four, the yellow- 

 banded rattlesnake, the prairie rattlesnake, the coral snake, and the 

 copperhead, are poisonous. It is possible that the poisonous southern 

 moccasin, or cottonmouth, may yet be found in the southwestern part 

 of the State ; if so, we shall have live poisonous species, and five 

 only. 



Key to the Classes. 



A. Skin usually smooth and soft, sometimes rough and warty, 

 never forming scales that overlap or are arranged in regular 

 rows; eggs usually laid in the water and giving origin to 

 tadpoles.* (Water-dogs, salamanders, frogs and toads.) 



Batrachia, p. 5. 



AA. Skin usually having epidermal scales or large regular plates ; 

 these usually arranged in a regular manner, often overlap- 

 ping. Eggs laid on land. Young with form of adults. 

 (Snakes, lizards, turtles, alligators, etc.) Reptilia, p. 73. 



BATRACHIA. 



The Batrachia include a great variety of animals that are found living 

 in all except the coldest parts of the earth and the salt water. As al- 

 ready stated, they are, with rare exceptions, hatched in the water, 

 where they spend at least a portion of their lives. A few forms retam 

 their gills throughout life, and seldom or never leave the water. In a 

 few cases the eggs are laid on the land, under sticks and stones ; the 

 young from such eggs may have very rudimentary gills and consequently 

 never enter the water. Such species closely approach, in their habits, 

 the reptiles. The gills may be either internal or external ; usually they 

 are of the latter kind. The external gills are attached to processes of 

 the skin, and not to the branchial arches. The internal gills of the tad- 

 poles or frogs grow out from the branchial arches, as in fishes. 



The skin of the batrachians is richly provided with glands. These 

 secrete a milky fluid, which is often acrid, and sometimes poisonous to 

 the enemies of the species producing it. It thus serves as a means of 

 defense to these animals, which are otherwise almost helpless.. Often 

 the glands are collected into groups, as in the case of those on the back 

 of the head of the common toad. In some species the skin forms a fin 

 on the upper and lower sides of the tail ; but in such fins there are no 

 rays, such as are found in the fins of fishes. 



