774 The American Naturalist. [September, 
this period that they belonged to some species of tree-frog, since 
the hinder digits were furnished with disks ; as were also the fin- 
gers even before they were set free. No stripes were yet visible. 
As the tail shows signs of absorption the body continues to shrink 
in size, probably owing to the shortening of the alimentary 
canal. The dorsal stripes also begin to appear, so that it becomes 
easy to recognize the species. 
They now show a decided inclination to leave the water. They 
climb up the sides of the aquarium ; and to keep them in netting 
must be put over it. Having no web on their feet they are poor 
swimmers, and many of them were found drowned. When free they 
doubtless early leave the water, and hide away among the sticks 
and leaves, where they are protected, and can find suitable food. 
By the first of June many of the larvae had lost nearly the 
whole of the tail. Others were slower in development, and it 
was not until the I2th of June that all had completely transformed. 
Twenty-five or thirty af these were shut up in a box containing 
dirt and chips, and covered with netting. An attempt was made 
to furnish them with insect food, with the intention of watching 
them further. They hid away under the chips, and lived for some 
days ; but they grew emaciated, and many died, and the effort to 
raise them was abandoned. 
I doubt much that this species is, to any considerable extent, 
a tree-inhabiting frog. Such specimens as have been taken where 
I could learn of the circumstances have been captured in the 
grass. Dr. Coues states, in the " Bulletin of the U. S. Geologi- 
cal Survey," IV., p. 290, that it was found in the greatest abund- 
ance in prairie pools and streams in Northern Dakota and Mon- 
tana. Some of them were taken at Frenchman's river on the ist 
of July. It is probable that even at that late season they were 
depositing their spawn. 
EXPLANATION OF PLATE XXXV. 
Fig. I. Adult frog of natural size. 
Fig. 2. Egg on March 22, with contained larva. A, gelatinous en- 
velope around ^^g ; IVI, mouth. 
Fig 3. Larva on 28th of March, straightened ; Na. external nares ; 
