550 EEKTKAM G. SMITH 



With the transition from the water to the land, or vice versa, 

 one might expect important modifications in the sense organs. 

 In the amphibia this expectation is best reahzed in the auditory 

 organs, which in the form of a columellar apparatus fitting into a 

 fenestra ovaHs here occur for the first time in the vertebrate 

 series. From a study of the modifications of this apparatus we 

 may well hope to obtain information concerning the more inti- 

 mate phylogenetic relationships within the group. According to 

 the recent work of Kingsbury and Reed ('09) on the urodeles, 

 there is close correlation between the type of auditory apparatus 

 present and the habits (aquatic, semi-aquatic, terrestrial, burrow- 

 ing, etc.) of the animals. From their results one may note many 

 resemblances between the adults of the typically aquatic forms 

 and the aquatic larvae of the terrestrial forms, as well as con- 

 trasts between both of these and the adult terrestrial forms. 

 Concerning the phylogenetic relationships as indicated by the 

 auditory apparatus Reed ('09) says: 



Cryptobranchus is the most generalized. The ambl3^stomidae are 

 intermediate between Cryptobranchus and all other groups. Th(^ p\e- 

 thodontidae and desmognathidae are departures from the Amblys- 

 toma stem while from these the sirenidae and Amphiuma seem to be 

 degenerated. Diemyctylus and Triton are identical with regard to 

 these ear structures and (hffer from all others. They are to be consid- 

 ered the most specialized. Between Diemyctylus and Triton on the 

 one hand and the amblystomidae on the other Salamandra stands inter- 

 mediate, resembling more strongly the amblystomidae. 



If the generalized condition is really a primary one, then so 

 far as the evidence from this single character is concerned, Cryp- 

 tobranchus is one of the most primitive of urodeles ; the evidence 

 is not in line with the hypothesis of Versluys. But one should 

 seriously consider whether the correlation between the sound- 

 transmitting organs and the environmental relations is not too 

 close to make the character of nmch phylogenetic value. 



Osborn ('88) states that in Cryptobranchus we have the most 

 primitive type of brain thus far observed among the amphibia. 

 But it is not clear that the simple condition found is necessarily 

 primitive. 



