1887] Oviposition and Nursing in the Genus Dendrobates. 309 
similar to'that I have described and in the same region; this he 
secured, and it is now in the possession of Professor E. D. Cope. 
Mr. Smith writes me: “Four of the young, I believe, dropped 
off and were lost; being in-a hurry, I threw the frog at once into 
a bottle of alcohol, and I did not observe how the young were 
attached to the back.” 
These very imperfect observations are all that I can give con- 
cerning the habits of this very singular batrachian, but I hope 
that they may serve to direct the attention of other naturalists 
to these species. The Santarem frog mentioned above was simi- 
lar in form to this one, though a good deal larger, and very likely 
it belongs to the same genus. In view of my observations on the 
chapadao species it seems probable that the information given by 
the hunters was correct, and that the Amazonian frog also carries 
its young on its back. 
In both cases there seems to be an evident adaptation of the 
habits to the surroundings. The Santarem forests are always 
moist and comparatively cool, but the absence of standing or 
running water in those parts where the frog is seen would pre- 
vent the ordinary disposition of its young. The varzeas, on the 
contrary, are wet and even partly flooded after rains; but even 
in the height of the rainy season the pools and streams may dry 
up if a few days pass without showers. If the young frogs were 
left in the water they would run the risk of being destroyed be- 
fore their development was completed. In the dry season the 
frog, like most other animals, disappears from the varzeas ; prob- 
ably it retires to some crevice where it can*remain sheltered until 
the rains set in again. Both the frogs observed with young were 
, seen at the beginning of the rainy season. 
It would be interesting to know how the young (or eggs) are 
first placed on the back of the parent and how they are nour- 
ished. . 
I may notice here that the bright spots on the legs of this frog 
and of other species serve in a very curious way to conceal the 
animals, They are only visible when the frog is hopping, and 
their sudden disappearance when the animal comes to rest causes 
one to lose sight of it altogether; for the eye naturally follows 
the bright colors, and perhaps they have the effect of momenta- 
rily dazzling it, so that the sombre general surface of the frog, 
very like the ground on which it sits, becomes for an instant 
