610 
have been questioned by Norris (1902), who finds that these strue- 
tures have no direct association with the epithelium of the branchial 
chamber whatever, but that they take the place of a portion of the 
M. basi-hyobranchialis when it degenerates at transformation. He 
therefore proposes to substitute the older name, (Glandula pseudo- 
thyroidea), for the term applied by MAURER, — Kiemenrest, — which 
in any case is not very appropriate, — as from his results it is parti- 
cularly meaningless and inapplicable. The mode of development of 
the so-called Kiemenreste hence calls for renewed investigation. 
Should MAURER’S interpretation be found to hold, there would seem 
little doubt that both types of organs,—tonsils and Kiemenreste, — 
belong in the same category. Even if the contention of Norris prove 
correct, there would still be a common developmental feature in that 
both structures appear at points marked by involution or the re- 
absorption of differentiated structure. 
SUMMARY. 
1. Structures having the histological characteristics of tonsils 
occur in connection with the oral (pharyngeal) epithelium in Amphibia. 
2. In Salamandra atra tonsils occur in some twelve localities. 
They exhibit considerable variability in occurrence and location. 
3. In four regions their location is definite and constant enough to 
warrant the application to them of locative names. They are there- 
fore designated the Choanal, Lateral, Sublingual, and Preglottideal 
Tonsils. 
4. In structure they possess the following characteristics; (a) an 
accumulation of round cells beneath and within the epithelium; 
(b) thickening of the epithelium; (ce) intimate relations to the blood 
vessels. 
5. Mitotic figures occur in the tonsils and there is evidence that 
they are centers for lymphocyte formation. 
6. In other amphibia; — sublingual and lateral tonsils occur 
in Desmognathus fusca, sublingual tonsils in Amblystoma punctatum, 
lateral tonsils in Diemyctylus and Plethodon. None were found in 
a Gyrinophilus porphyriticus. In Bufo (lentiginosus) sublingual 
tonsils are of constant occurrence. 
7. The sublingual, lateral and preglottideal tonsils of Salamandra 
atra occur at sites which in the metamorphosis are marked by absorp- 
tion, particularly or more evidently of epithelium. 

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