REPTILES. 



405 



Among the strangest of the lizards are the Amphisbsenas, the name of 

 which means walking in either direction. To a casual glance both ends of 

 the animal are alike, and in their motions the head seems to have but 

 little preference over the tail, as they wiggle in either direction with 

 almost equal facility. These facts have given rise to the fable that they 

 have two heads, one at either end of the body. In South America they 

 live habitually in the subterranean burrows of the saiiba ant, and the 

 natives call them ' mai das saiibas,' — mother of the saiibas. " They say 

 that the ants treat it with great affection, and that if the snake be taken 

 away from the nest, the saiibas will at once forsake the spot." This prob- 

 ably partakes of the nature of a myth ; and although the relation which 

 exists between the ants and the Amphisbsena is not yet certainly known, 

 there is considerable probability that the association is of considerable 



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AUG.NEUMKNN- V 



Fig. 353. — Ainphisbaena. 



advantage to the lizard ; for, on dissection, remains of ants have been found 

 in their stomachs. 



In the quotation given in the preceding paragraph this animal is called 

 a ' snake,' and a snake it is in appearance, but not in structure. It has no 

 legs, its body is of nearly the same size throughout ; but in all the feat- 

 ures of its internal anatomy it is seen to agree thoroughly with the lizards. 

 It reaches a length of about a foot. 



These forms lead us in a line of degeneration. There is no doubt but 

 that these slow-worms and Amphisbaenas have descended from more 

 normal lizards, and that the whole tendency of their development is away 

 from the typical line, and one which tends to the loss of everything char- 

 acteristic of a lizard. In the next forms, the chameleons, the tendency is 

 in exactly the opposite direction, — the specialization of all lizard features. 



What more vivid description can there be of the chameleon, the strange 

 form represented upon our plate, than the following of nearly three hun- 



