Hinckley.] 
308 
[January 4, 
black, and edged with numerous sharp, pointed teeth. The upper 
jaw (fig. 2. c.) is larger and projects beyond the lower jaw 
(fig. 2. d.), so that when the month is closed the latter is not seen 
at all. Overlapped by the upper lip and running parallel with 
it, at each side the upper jaw, are two fleshy folds the free edge 
of which is fringed with what appears by the aid of a magnifying 
glass a row of narrow, rigid, black, closely-set tines or teeth, uneven 
in length, and sometimes in width, with a tendency to hook 
inwards. With occasional exceptions in the tadpoles of Rana 
catesbeiana, the edge of the upper lip, in all the species to be 
described, is itself fringed in like manner. Crossing the pendent 
under lip, are three folds (fig. 2. e.) reversed as to the position of 
the fringed edge from those under the upper lip. The mar- 
gin of the under lip forms a border which extends up to, and 
joins, the upper lip. Excepting in the tadpoles of Bufo ameri- 
canus, B. fowleri and Hylodes pickeringii, this border (fig. 2. f.) 
is entirely edged with a row of papillae, more or less papillae 
being also found within it each side of the mouth. The papillae 
vary in color, size, number and position. 
One of the purposes of this papillose edge is, apparently, to 
test the nature of the objects the tadpole comes in contact with, 1 
and the stiff fringe along the edge of the lips and folds, serves to 
collect and hold their food. These fringed folds are perfectly 
free, excepting at their base ; those on the under lip are usually 
held at an angle from the lip ; but are capable of being laid back 
as is shown when the tadpole wishes to reject any substance held 
by the fringe. The upper jaw is stationary, but both upj)er and 
under lips are employed the greater part of the time in col- 
lecting and conveying food to the jaws. Although one might 
suppose that nothing eatable comes amiss to a tadpole, it may be 
observed that much is rejected after it has been tried between the 
jaws, and, apparently lest this may be entangled in the fringes, it 
is expelled with considerable force from the corners of the mouth. 
The result of my observations goes to prove that the food of 
the different tadpoles, after they leave the gelatinous substance 
surrounding the eggs which they commonly feed upon first, con- 
1 Van Bambeke. Recherches sur la structure de la bouche chez les tetards des 
Batraciens anoures. Bull, de l’acad. royale de Belgique. 2e ser., t. xvi, p. 342. 
