200 ANIMAL FORMS 
probably the same is true of the crocediles and alligators 
and some of the larger snakes. Their enemies are few, and 
death usually results when the natural course is run. 
Throughout life all reptiles periodically shed their skin, 
as birds do their feathers and mammals their fur. In the 
snakes and some of the lizards the skin at the lips loosens, 
and the animal gradually slips out of its old slough, bright 
and glossy in the new one which previously developed. In 
the others the old skin hangs on in tatters, gradually com- 
ing away as they scamper through the grass. 
