The Columella Auris in Amphibia. 591 



that the proton described by her might represent "a true columella 

 or hyomandibular cartilage which may become fused with the true 

 operculum," although he could find no trace of such a double origin. 

 In comment on the above it may be said that to determine the first 

 development it is necessary to go back of the condition in a 26 mm. 

 larva as was done by Miss Piatt. There is certainly no indication 

 of a double origin, although the increase in size in the columella of 

 Necturus, as in Ambystoma (p. 556), admits of two possibilities of 

 interpretation. The development of the operculum as described by 

 Stohr in Triton and Siredon has been discussed on p. 573. 



The ramus jugailaris VII passes over the ligament (PI. VIII, 

 Fig. 58), as in Proteus and Typhlomolge described above. 



The relations of the columella, squamosum and facial nerve in 

 N^ecturus are well known through the work of Cope, Driiner, Kings- 

 bury and Wilder, though the significance of the relations has not 

 been adequately considered. 



Huxley's classic paper on the skull of ISTecturus was in respect 

 to his description of the relation of the columella, facial nerve, and 

 suspensorium incorrect and misleading, occasioning a wrong idea 

 of the urodele type, persistent even up to the present time. We find 

 no trace of his ligamentum suspensorio-stapiale, over which the 

 facial nerve passes. Operculum (our use) and M. opercularis are 

 1 acking. 



Proteus agrees in all essentials with ISTecturus (Wiedersheim, 

 Driiner, Kingsbury). 



Ckyptobeanchibae. 



Cryptobranchus allegheniensis. Through the generosity of Mr. 

 B. G. Smith, of Syracuse University, who kindly sent us a series of 

 embryo, larval and adult specimens, we were enabled to examine the 

 relations in this interesting form with quite satisfactory results. 



As the publications of Wiedersheim ('77), Parker ('82b) and 

 Cope ('88) have shown, the Columella in the adult possesses a well 

 developed stilus which articulates with the under (inner) surface 

 of the squamosum. This relation is strikingly shown in the series 

 of sections through the head of an adult 140 mm. long (PI. VII, 



