the frog answers back to light rays as well. Professor Yerkes
experimented with a frog which had to go through a simple labyrinth if
it wished to reach a tank of water. At the first alternative between two
paths, a red card was placed on the wrong side and a white one on the
other. When the frog had learned to take the correct path, marked by the
white card, Prof. Yerkes changed the cards. The confusion of the frog
showed how thoroughly it had learned its lesson.

We know very little in regard to sense of smell or taste in amphibians;
but the sense of hearing is well developed, more developed than might be
inferred from the indifference that frogs show to almost all sounds
except the croaking of their kindred and splashes in the water.

The toad looks almost sagacious when it is climbing up a bank, and some
of the tree-frogs are very alert; but there is very little that we dare
say about the amphibian mind. We have mentioned that frogs may learn the
secret of a simple maze, and toads sometimes make for a particular
spawning-pond from a considerable distance. But an examination of their
brains, occupying a relatively small part of the broad, flat skull,
warns us not to expect much intelligence. On the other hand, when we
take frogs along a line that is very vital to them, namely, the
discrimination of palatable and unpalatable insects, we find, by
experiment, that they are quick to learn and that they remember their
lessons for many days. Frogs sometimes deposit their eggs in very
unsuitable pools of water; but perhaps that is not quite so stupid as it
looks. The egg-laying is a matter that has been, as it were, handed over
to instinctive registration.

[Illustration: _Photo: W. S. Berridge._

HARPY-EAGLE

"Clean and dainty and proud as a Spanish Don."

It is an arboreal and cliff-loving bird, feeding chiefly on mammals,
very fierce and strong. The under parts are mostly white, with a greyish
zone on the chest. The upper parts are blackish-grey. The harpy occurs
from Mexico to Paraguay and Bolivia.]

[Illustration: _Photo: W. S. Berridge, F.Z.S._

THE DINGO OR WILD DOG OF AUSTRALIA, PERHAPS AN INDIGENOUS WILD SPECIES,
PERHAPS A DOMESTICATED DOG THAT HAS GONE WILD OR FERAL

It does much harm in destroying sheep. It is famous for its persistent
"death-feigning," for an individual has been known to allow part of its
skin to be removed, in the belief that it was dead, before betraying its
vitality.]

[Illustrati