HYO-BRANCHIAL APPARATUS OF TYPHLOTRITON. 171 



1. Spelcrpes bilineatus which is not found in caves to any 

 degree. 



2. Spelerpes longicauda resembling the first form, but often 

 called a cave salamander, although it may be found out from 

 caves now and then. 



3. Spelerpes manculicaudus. More properly a cave form and 

 closely resembles the next form in many ways on the one hand, 

 as well as longicauda on the other, but has well developed eyes. 



4. Typhlotriton, found in caves. Has lost the use of its eyes 

 and is truly a cave form. 



5. Typhlomolge rathbuni which is found in deeper caves and 

 seems to be a permanent larva or the larva of an adult closely 

 related to Typhlotriton and Spelerpes. 



LABORATORY OF HISTOLOGY AND EMBRYOLOGY, 

 CORNELL UNIVERSITY, ITHACA, N. Y. 



