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Family II. CAUDATA. 



CHARACTERS. 



1. The presence of a tail, at all periods of their existence, readily distinguishes 



the animals of this family from those of the last, though it varies in length 

 and in form. 



2. The body is elongated, round, and covered with a skin adherent to the 



muscles beneath. 



3. The extremities vary in number; there may be four, (Salamandra,) or two, 



(Siren.) 



4. The tongue varies in shape, size, and mode of attachment. 



5. The tympanum is not visible. 



Remarks. Fitzinger makes a very natural subdivision of this family into two 

 tribes. 



Mutabilia, or such as undergo a metamorphosis, as Salamanders; and 



Immutabilia, or such as are hatched with the forms they are permanently to 

 retain, like the Siren. 



