47] THE NA SA L ORG A N IN A MPHIBIA —HIGGINS 47 



His conclusion is based largely upon the absence of certain cranial bones, 

 such as the nasals, prefrontals and maxillaries, which are present in other 

 Urodeles. Rudimentary nasal capsules exist in the larvae of both Speler- 

 pes and Necturus, and in the former a completely developed capsule is not 

 present until a relatively late period, correlated with its retarded meta- 

 morphosis, the individual often not transforming until two or three years 

 after hatching. On the basis of the nasal capsule, I am inclined to regard 

 Necturus as a permanent larva, possibly related to the other Urodeles 

 through a Spelerpes-like ancestor. The retention of the larval characters 

 of the trabeculae and of the planum basale can certainly not be regarded 

 as ancestral, nor can degeneration alone explain the present structure of 

 the capsule of Necturus. 



The phylogenetic position of the Gymnophiona has occasioned much 

 diversity of opinion. Huxley (1875) stated that there was not the slightest 

 indication of any approximation to either the Anura or the Urodeles. On 

 the other hand, Cope (1889) even placed the family Caecilidae among the 

 Urodeles, and regarded them as degenerate and related to the main line 

 through Amphiuma; while the Sarasin cousins (1890) took the position 

 that Amphiuma was a neotenic condition of the Caecilian. Kingsley 

 (1902) discussed the views of both Cope and the Sarasins and established 

 the conclusion, now generally accepted, that the Gymnophiona are to be 

 regarded as distinct from either Urodela or Anura and placed in a separate 

 order. 



The nasal capsule of Epicrium presents little of classificatory value, 

 except that it presents only distant resemblances to the characteristic 

 Urodelan capsule. In the presence of dorsal and ventral trabeculae, Epicrium 

 differs from all other Urodeles where the alisphenoid and trabecula are 

 continuous and form the lateral wall of the cavum cranii. In the earlier 

 stage, which Winslow studied, the ventral trabeculae unite to form the 

 planum basale, but there is no extension forward of the trabeculae into 

 cornua as in Urodeles; although in my earlier stage, which is considerably 

 later than that of Winslow, small processes occur at the anterior margin of 

 the basale, the probable tips of the trabeculae. The solum nasale, how- 

 ever, or floor of the capsule which unites the lamina externa to the planum 

 basale, is a modified cornu, which in the older stage especially, is greatly 

 removed from the position of the cornu trabeculae in Urodeles. The 

 antorbital process, a lateral growth from the trabecula in the early stage of 

 Winslow, later unites to the other parts of the capsule, as in Urodeles, 

 bounding the orbito-nasal foramen. That the antorbital was at one time 

 related to the parts of the pterygoid just posterior to it, is suggested by a 

 sharp protuberance on its ventral margin toward the small independent 

 part of the pterygoid; so that it would appear as if the processus antor- 

 bitalis and pterygoid cartilage of Epicrium were at one time united as in 



