FROGS, TOADS, SALAMANDERS, SNAKES, ETC. 163 



The latter three are found only in the South. Rattlesnakes are 

 found in almost all parts of the United States, but have been 

 nearly exterminated in the more settled regions. Before 

 striking with their poisonous fangs, they give a warning by 

 means of the " rattle " at the end of the tail. This consists of 

 a number of horny, thin, joint-like structures. These are the 

 remnants of previous coats of skin which did not fall off with 

 the shedding of the rest. It used to be said that each section 

 in the rattle indicated one year in the snake's life. This is, 

 however, not the case, as it is now known that the snake 

 may shed its skin more than once a year. 



Do not forget the Turtles. Every child is interested in 

 them. Keep some at the school. The smaller ones may be 

 placed in the aquarium, but a float or raft should be pro- 

 vided for them. Larger ones may be kept in a terrarium. 

 Observe the feeding and other habits of these specimens. 

 Note how they swim. Have they any teeth? Note how 

 well the softer parts of the body are protected. The shell of 

 the hard-shell turtles is made of a modified bony skin, grown 

 together with the backbone, ribs, and breastbone. Are the 

 colors of the shell protective? Hold a turtle under water 

 and note the transparent film, the nictitating membrane, 

 that is drawn over the eyes. In the fall a turtle in a 

 cage with an earthen floor will be seen to be anxious about 

 something, and trying to burrow into the ground. It is 

 getting ready for the hibernation. If a deep lot of earth is 

 put into the box the turtle will probably completely bury it- 

 self, particularly if the box is left in a cool place. 



The soft-shelled, snapping, mud, and box turtles are the 

 commonest in the Northern States. Let the children know 

 about the large sea-turtles, such as the loggerhead, hawks- 



