605 
lie at the side of the back part of the tongue, as shown in figure 2, 
which may be compared with figure 13, as of a nearly comparable level 
in a nearly transformed larva. The development of the adult tongue 
causes a piling up of the epithelium in this region with a marked attend- 
ing histolysis, so that it is not easy to determine what point of 
morphogenetic correlation there may be between the appearance of 
the tonsils and the transformations at metamorphosis, as the region 
is difficult of analysis and this is true notwithstanding the fact that 
the sublingual tonsils are, after the preglottideal tonsils, the most 
constant in occurrance and location. 
In the toad, while the morphological relations are in some respects 
more complex, nevertheless because of its constancy, it is possible to 
locate more ex- 
actly the point at 
which the sublin- 
gual tonsil appe- 
ars (Fig. 14). It 
is thus found to 
be at the cephalic 
end of the furrow 
(II) leading for- 
ward from the if 
a = . Fig. 14. Sublingual Tonsils. Bufo lentiginosus. To show 
branchial cham their general location in relation to the tongue. >< 221/,. 
ber. The devel- T. Tonsil. 
opment of the 
tongue, while proceeding in anura essentially as in urodela, does 
not, directly at least, influence the transformations in the tonsillar 
region. Hence, also there is little doubt as to the interpretation in 
Salamandra. 
Other Amphibia. While a detailed study of the tonsils in other 
urodela amphibia has not been made, enough has been done to indicate 
clearly that the regions in which tonsils occur in Salamandra atra 
are also those in which they occur in other salamanders. Thus in a 
single adult specimen of Desmognathus fusca were found (1) lateral 
tonsils, double on each side, apparently representing III (b) and (ce); 
(2) paired sublingual tonsils in the typical position over the expanded 
ceratohyals; (3) a conjunctival tonsil upon the right side. A preglotti- 
deal tonsil was lacking and this was rather to be expected since the 
glottis itself is lacking, this form being one of the lungless salamanders. 

