1882 .] 
309 
[Hinckley 
tinues to be, by choice, animal rather than vegetable. On the 
death of one of their number, and even before this event has really 
taken place, the companions proceed at once to devour all but the 
bony skeleton ; and indeed the best means of securing the skele- 
ton in its most perfect condition is to leave the preparation of it 
to the living tadpoles. 
The difference which first arrests the attention in the mouth is 
the form given it by the lips. This character divides the tadpoles 
under consideration into three groups. The first contains two 
tadpoles which agree in having a broad, even, upper lip fringed at 
the edge. The margin of the under lip forms a border which 
extends up to and laps on the upper lip ; the edge of the border 
doubles inward at both corners of the mouth. Excepting the 
wide space at the edge of the under lip which is fringed, the 
border terminates in a papillose edge; the space in the border 
occupied by the fringe is deeper by the width of the fringe than 
the adjacent part occupied by papillae (fig. 3). This form of 
mouth is found in the tadpoles of the toads Bufo americanus 
Leconte, and B. fowleri Putnam. 
The second group also contains two tadpoles which agree in hav 
ing a broad, fringed upper lip gradually lengthened from the mid- 
dle into two deep curves. The border instead of doubling inward 
at the corners of the mouth is continuous to the union with the 
upper lip. The papillose edge of the border overlaps the upper lip 
about one-third its entire length on each side. The papillae are 
small and those within the border are closely set near the edge 
(fig. 4). The tadpoles of this group develop into frogs having the 
toes expanded into adhesive discs, Hyla versicolor Leconte, and 
Hylodes pickeringii Holbrook. 
In the third division we have five tadpoles which agree in 
having a short and narrower upper lip than the others have 
shown. The margin of the under lip terminates in a papillose 
edge which is doubled inward at each corner of the mouth and 
laps on the upper lip to which it extends (fig. 7). The tadpoles 
of this group are those of the frogs Rana silvatica Leconte, R. 
catesbeiana Shaw, R. fontinalis Leconte, R. halecina Kalm, and 
R. palustris Leconte. 
For convenience of comparison the figures intended to repre- 
sent the mouths are not given with reference to relative size. 
