TAILED BATRACHIANS 257 



yellow, the coloration, both above and below, is of a 

 uniform dark brown. 



In T. andersonii, of the Loo Choo Islands, the ribs are, 

 as in M. zvaltlii, long and pointed, and perforate the skin. 



Amblystoma is represented by twenty species, which, with 

 the exception of A. persimile, a native of the mountain 

 regions of Siam, are inhabitants of either North or Central 

 America. The majority resemble in shape the European 

 Salamanders, the head being short and broad, with 

 prominent eyes, while the somewhat heavy, elongate body 

 is grooved laterally. The limbs are well developed, with 

 five toes. The tail is more or less compressed and usually 

 somewhat shorter than the head and body. 



Like the true Salamanders the Amblystomes live con- 

 cealed under moss, leaves, and stones, leaving their retreats 

 but once a year, when they congregate in pools or ponds in 

 order to lay their eggs. 



A. tigrinum is one of the commonest species, being very 

 abundant throughout North America and southwards to 

 Central Mexico. The skin is smooth and shiny, black 

 in colour, spotted or blotched with yellow ; the under- 

 surfaces are slate grey, with a few very small white spots. 



The larva of this salamander, which attains a length of 

 nearly a foot, is of peculiar interest on account of the fact 

 that in Mexico, where it is known under the name of 

 AxoLOTL, and where it forms a popular article of food, it 

 rarely transforms, but remains in the water throughout life, 

 breeding in the imperfect condition. Its head is very 

 large and provided with three pairs of external gills ; the 

 tail is provided, both above and below, with a very broad 

 fin, which, in the case of the former, is continued along the 

 back to the head. 



