THE RATTLESNAKE 143 



but are enclosed in a leathery case, oblong in shape. 

 The pythons actually incubate their eggs, as was first 

 ascertained in the Jardin des Plantes at Paris. The 

 female arranged her eggs in a conical heap and twined 

 herself around them, her ever- watchful head surmounting 

 the summit of the cone. The period of incubation will 

 last two months, during which she will not feed, though 

 she has been known to drink copiously if water were 

 presented to her by her keepers. In spite of the generally 

 cold-blooded condition of snakes (as of other reptiles), it 

 has freen well ascertained that the temperature of the 

 mother is raised distinctly higher than that of the sur- 

 rounding atmosphere during the process of incubation. 



Various forms of small snakes, which here need not be 

 separately noticed, lead us to our last section (D). 



Its members indeed widely differ from all those I 

 have hitherto described. Not only is the head small, but 

 the small jaws are quite incapable of that mobility which is 

 so extraordinary and so characteristic of snakes generally. 

 Within their little mouths there are only a very few 

 simple teeth, the lower jaws and the palate having none. 

 Like the boas, they have rudiments of hinder limbs 

 beneath the skin. 



These snakes have the habits of earthworms, whence 

 they are often termed "burrowing snakes," and many 

 species are very much smaller than any ordinary earth- 

 worm. Their body is about the same size throughout, 

 being clothed with small smooth scales in harmony with 

 their burrowing habits. They have but a rudimentary 

 eye. None of them are poisonous ; their food consists of 

 grubs, insects, and other small creatures. They are 

 found all over the warmer regions of the world, especially 

 in Asia and Australia. They are numerous in America, 

 but extend to the shores of the Mediterranean and Japan. 



