224 INTELLIGENCE IN LOWER VERTEBRATES 
red color with the irritation caused by the tentacles so that 
the red came to be a “warning color.” Subsequently un- 
colored Atherinas were given them which were for the most 
part instantly taken. Red Atherinas were offered after 
an interval of eight days when they were very sparingly 
taken and then refused entirely, and again after an interval 
of twenty days when they remained entirely untouched. 
There are a number of instances of fishes coming to-be fed 
when a bell was rung or some other sound made, but it is 
probable as Kreid] has shown in one instance that the fish 
associated the food withthe appearance of the person 
making the sound rather than with the sound itself. 
The memory of topographical relations seems to be well 
developed in certain fishes as in certain insects. It is mani- 
fested most clearly in those forms which have a more or 
less fixed habitation or which build a nest for their eggs. 
A good illustration of this faculty is afforded by a species 
of Goby studied by Mlle. Goldsmith. This species, Gobius 
minutus, is commonly found in tide pools under a shell of 
some bivalve mollusc where it may lie half buried in the 
sand. That the fish recognizes its shell by sight is shown 
by the fact that when Mlle. Goldsmith drove a specimen 
from under its shell and placed the aquarium where it was 
kept in the dark the fish did not succeed in finding its shell 
during twenty-four hours: when light was admitted it dis- 
covered the shell at once. The experiment was repeated 
many times with different individuals, with the same result. 
The ability of Gobius to learn a certain path to its shell 
is shown in the following experiment: A goby was placed in 
an aquarium divided in the middle by a glass plate which 
left a narrow passage way at one end. The shell of the 
goby was placed in one compartment C and the fish was 
driven through the passage way into the adjoining part of 
