14 INEZ L. WHIFFLE. 



gradually as the animals grow older. The smallest showed three 

 or four only, the more ventral of these being very short. A 

 specimen 43.5 mm. long had six in connection with each groove, 

 while in a large adult as many as twelve are often present. 



The extent of the glands also increases as the animals grow 

 larger, a fact which has already been mentioned as throwing light 

 upon the relation of the glands to other glandular masses. One 

 very interesting fact is that the tubule which enters the nerve 

 foramen in the premaxillary does this previous to the roofing 

 over of the foramen. It thus lies at first on the surface of the 

 premaxillary in a mere groove which later becomes enclosed 

 to form a foramen. 



THE HOMOLOGY OF THE NASO-LABIAL GLANDS. 



There seems to be no reason why the homology which Bruner 

 ('96) has assumed to exist between the external nasal glands of 

 all of the Salaniandrida and Anura should not be accepted for 

 the Desmognathidcz and Plcfhodontidce, in spite of the greater 

 extent and more external position of the glands in these families. 

 This homology will of course include strictly only those two of 

 naso -labial group which open upon the border of the naris, and 

 is based upon similarity of origin and structure between these and 

 the external nasal glands of lunged forms. There is, however, 

 absolutely no reason for considering the remainder of the naso- 

 labial glands as in any essential unlike these two, and the entire 

 group must, of course, be homologized together. 



Moreover, I have obtained sufficient evidence (which will be 

 given in a separate paper) to prove that the large gland which 

 occurs in Ampliiuina and was described by H. H. Wilder ('91) 

 under the name of the " glaiidida lateralis" is also the homo- 

 logue of these glands as well as of Oppel 's glands of Proteus. 

 The homology of all these glands becomes especially emphasized 

 when we recall that in many of the lunged forms the external 

 nasal glands consist of many tubules opening by separate orifices. 

 Thus Bruner reports for one specimen of Aiidilystoma fifteen 

 independent tubules. 



To go back of the adult condition and determine the source 

 from which these external nasal and naso-labial glands were 



