14 



PROCEEDINGS OF THE ACADEMY OF 



[Jan., 



There are several examples of independent and parallel evolution 

 in these genera. The most obvious is the loss of a toe, which has 

 been undoubtedly independent in the three reduced genera. . The 

 loss of the prefrontal in Batrachoseps and the Desmognathus group 

 is another case. The consolidation of the premaxillaries has probably 

 been independent, likewise the acquiring of terrestrial habitat. 

 A scheme is here added, followed by a key to the genera, which 

 may show more clearly the relationships as understood by us. 



