48 ILLINOIS BIOLOGICAL MONOGRAPHS [48 



Cryptobranchus, but the now intimate association of the former with the 

 nasal capsule indicates that the Caecilian probably is far removed from 

 ancestral conditions. 



Epicrium is more like Amphiuma, of all Urodeles, although differing 

 greatly from it. The greater similarity lies in the origin of the planum 

 verticale from the median line of the basale and in the subsequent develop- 

 ment of the alary processes which, in the later stages of both, partially 

 cover the dorsal surface of the nasal sac. Further similarity lies in the 

 modification of the cornu trabeculae which in both, forms the floor of the 

 capsule, uniting the planum basale to the lower margin of the lamina 

 externa, and partially supporting the nasal organ. 



On the other hand, the parallel rods of cartilage which in Epicrium form 

 the lateral wall of the capsule anterior to the solum nasale, uniting anter- 

 iorly with the alary process to form a partial vault, do not exist in Amphi- 

 uma, where the united elements of cornu and lamina externa expand into 

 an oblique circumnarial ring. Further, the antorbital process of Amphiuma 

 never unites to the capsule as in Epicrium, nor at any stage does a complete 

 columna ethmoidalis exist in the latter form, so that there are many 

 contrasts between the capsules of the two. Thus upon the evidence 

 submitted by the nasal capsules, the position of Cope or Sarasin can not 

 be supported, all conditions pointing to the complete separation of the 

 Gymnophiona from the Anura or the Urodela. 



