Nest-Building Fishes. 167 
Marked differences in details of structure, configuration and 
surroundings are apparent, which prove that these creatures 
are controlled by reason, rather than instinct, in the elabo- 
ration of theirhomes. That they have some means of com- 
municating their desires to each other cannot be doubted. 
When the male has laid hold of a stem, a pebble ora stick 
that completely baffles all effort at removal, his mate seems 
summoned to his assistance, and the united strength of the 
pair accomplishes the object to be gained. There is ever 
noticeable in whatever the sexes undertake some concert of 
action which would put to shame the boasted intelligence of 
man himself. The Sun-fishes, as has been said, nest in com- 
panies. When the combined effort of two individuals is un- 
able to expel an invader, the entire community, as by a single 
mighty impulse, rises up against the foe. There is evidence 
of some form of society, even though simple in its organiza- 
tion, where individual members league themselves together 
for mutual protection and defence. Other examples might 
be cited to give the reader a common-sense estimate of the 
comparatively high order of intelligence that characterizes 
the actions of many of our fishes. 
