FACTS AP.OIT \VK[,I. KNOWN ANIMALS. 



96 



istics of the tadpole of the frog, its external brancliia) and 

 nioinl)ranous back ami tail, well fittini!; it for aquatic life. 

 Now this Siredon will either retain this larval form iM-rma- 



Fig. S. Amblysfoma mavortium Baird : a, larval form or SireJon lichenoides 

 Baird, side view; b, do., dorsal view ; c, mature form partially developed and cor- 

 responding lo ./. inncnlatiiin Hall. — all one-half natural size. (After Marsh.) 



nently and perpetuate itself, or else may become transformed 

 into a perfect salamander, under wliicli form it has been re- 

 ferred to another ^enus and described as Amhli/sloma mavor- 

 (inm. Not only are the dorsal and caudal membranes and 

 the external branchitc absorbed in the process, but the color 

 • •hanges, the size decreases, and profound changes take i)lace 

 in the external and bony structure. An allied sj)ecics from 

 the table-lands of Mexico, normally remains and breeds in 

 the Siredon state, but will sometimes cluinge, especially if 



