PHARYNGEAL DERIVATIVES OF AMBLYSTOMA 661 



Epithelial bodies and gill-remnants. Maurer ('88) was the first 

 to describe the genesis of the small epithelial-like structures in 

 close proximity to the glandular structures in the neck of the 

 adult amphibians, and was first to suggest that possibly these 

 could be looked upon as the homologues of structures in the higher 

 forms. He found that the epithelial bodies develop during the 

 time of the formation of the inner gills, from the ventral ends of 

 the third and fourth pouches of the tadpole of the frog, while 

 the gill remnants, ' Kiemenreste,' develop from the anterior ventral 

 region of the branchial chamber at the time of the reduction of 

 the gills. The carotid gland in Rana, according to Maurer, 

 develops in a similar manner, from the ventral end of the second 

 pouch, and was therefore considered by him as an epithelial 

 structure. (This origin of the carotid gland has been doubted 

 by other workers, especially Schaper ('96) and Zimmermann 

 ('98)). 



Norris ('02), studying the development in Rana fusca of the 

 so-called ventral Kiemenrest of Maurer, is unable to agree that it 

 is related in any way in its genesis with the branchial apparatus, 

 but says that it arises (during metamorphosis), in the region of the 

 body previously occupied by parts of the basi-hyobranchialis 

 muscle of the tadpole. In the urodeles, no such gill-remnants as 

 occur in anurans have yet been described. 



Maurer ('88) was the first to work out the development of the 

 epithelial bodies in the urodeles. In Triton taeniatus, he found 

 the bodies developed from the ventral portions of the third and 

 fourth pouches, not during the larval stage as in the case of 

 anurans, but during the metamorphosis, and in the adult those 

 came to lie close to the lateral (convex) wall of the aortic arches. 

 Maurer observed the formation of the carotid gland in the region 

 of the second pouch, during this same period, but whether it 

 developed from the cells of the transforming pouch he was unable 

 to say, although in the anurans th's seemed to him to be the case. 



Since Maurer wrote, very little work has been done on the 

 development of the epithelial bodies and gill-remnants in the 

 amphibians. Verdun ('98), refers to Maurer's work, and Mrs. 

 Thompson ('10), gives but very brief discussion of them in her 



