604 
83 mm., r.). The location thus given is neither a close nor exact one. 
The first locality (a) seems to be that of the caudal end of the region 
of the obliterated gill-openings, while the second (b) seems to cor- 
respond with the cephalic end of this region. Region (ec) is found where 
the hyomandibular fold of the larva (plica hyomandibularis, DRÜNER) 
has disappeared. 
The lateral tonsillar patches, therefore, do not appear to constitute 
a uniform group, but yet seem to possess a morphogenetic correlation 
with the obliterations taking place in this region at transformation. 
It should be appreciated, however, that the exact comparison 
of localities in the mucous membrane of larval and adult is rendered 
difficult by the shiftings in relation to underlying structures and the 
relatively long. interval between the completion of transformation 
and the appearance of the tonsillar patches. 
The region in which there appears the third of the tonsillar 
patches selected for more detailed study, the Sublingual Tonsil, 
is one of added complexity. In addition to the furrow representing 
the second gill cleft which in the larva extends approximately to this 
point, there is the development of the adult tongue which arises in 
front of the larval tongue and fuses with it, there being, according to 
Karrıvs, 1901, an attending absorption of the intervening tissue. 
The main features of the development of the tongue are readily follow- 
ed and the description and figures of KALLIUS are easily confirmed. 
The second furrow extends forward in the larva well toward the 
tip of the larval tongue. This furrow leads directly forward from the 
branchial chamber formed by the growths backward and downward 
from the second visceral arches to constitute the operculum. 
At transformation the operculum becomes fused with the under- 
lying structures, the epithelium of the branchial chamber being 
absorbed in the process. The furrow that leads forward from it, 
representing the second cleft likewise disappears and it becomes 
thus difficult to locate its cephalic end. An occasional epithelial 
remnant is however of assistance, as represented in figure 13. 
A careful and repeated study of the series of transforming and 
metamorphosed specimens of Salamandra atra has only permitted the 
statement that the sublingual tonsil occupies a place corresponding 
approximately to the region about the cephalic end of the furrow (II) 
leading forward from the branchial chamber. The expansion of the 
ceratohyale and the development of the adult tongue brings this to. 

