ORDERS OF AMPHIBIANS 



679 



Fig. 391. — Proteus anguineiis. — From a Specimen. 



The animal is 8-12 inches in length. There are three fingers and two 

 toes. The eyes do not reach the surface. There are three pairs 

 of gills. The tail is flattened. 



Fig. 392. — A limbless subterranean Amphibian (Ichthyophis).- 



From a Specimen. 



There are no epidermic scales, but there are calcareous platelets em- 

 bedded in tae dermis. There is a somewhat earthworm-like annula- 

 tion. The cloaca (CI.) is terminal, in contrast to its position in 

 the long-tailed limbless lizards. The resemblance between limbless 

 amphibian, limbless lizard, and burrowing snake illustrates 

 convergence — -the similar adaptation of unrelated types to similar 

 conditions of life — in this case, burrowing. 



