48 MARGARET H. COOK AND H. V. NEAL 
ing. In Catostomus and Coregonus taste-buds arise in the 
endodermal lining of the pharynx and are distributed over its 
surface and as far posteriorly as the opening of the air bladder. 
Johnston (’09, 710) finds even more positive evidence of the 
endodermal origin of the taste-buds in Amblystoma, in the 
embryos of which the pharynx is lined with endoderm ‘to the 
very lips.’ Taste-buds make their appearance within this endo- 
dermal-lined pharynx several days before the mouth breaks 
through. More direct evidence of the endodermal origin of 
the taste-buds could hardly be expected. Yet in this connection 
and in direct conflict with Johnston’s assertion that an ectodermal 
stomodaeum is wanting in Amblystoma, we have the evidence 
given by Kingsley and Thyng (’04) of a stomodaeal ingrowth in 
Amblystoma and of a considerable ectodermal invagination 
even before the mouth breaks through. While this evidence 
by no means disproves Johnston’s main contention that the 
pharyngeal taste-buds are endodermal in origin, it is sufficient 
to make doubtful the exact amount of ectodermal ingrowth and 
to this extent to open up the possibility of an ectodermal origin 
of the taste-buds. Landacre (’07) supports Johnston’s view 
of the endodermal origin of the taste-buds on the basis of obser- 
vations upon Ameiurus embryos. He finds, however, that the 
‘terminal-buds’ of the skin, which are so similar to the taste- 
buds, are ectodermal in origin. Keibel (712) holds that in man 
the taste-buds are “probably derived from the entoblast. The 
majority of the taste-buds lie undoubtedly within the ento- 
blastic territory, and even although epithelial encroachments 
are possible, yet it seems difficult to suppose that the ectoblast 
has penetrated into the region of the larynx.”’ 
The opinion that taste-buds are endodermal in origin seems 
strengthened by the evidence presented in sections of Squalus 
embryos. An examination of sections of the pharynx of this 
form shows that the whole pharyngeal cavity is endodermal in 
its origin and that there is little or no inward migration of the 
ectoderm into the pharynx except in the region of the upper and 
lower jaws, the epidermis of which is ectodermal. Until the 
time of perforation of the mouth and visceral clefts it is possible 
