242 
ANIMAL INTELLIGENCE. 
sideration, and also the fact that its brain is relatively 
much more massive as well as more highly organised than 
that which occurs in any other order of invertebrated 
animals, except, perhaps, the octopus and his allies. There- 
fore, although the brain of a fish is formed upon a type 
which by increase of size and complexity is destined in 
function far to eclipse all other types of nerve-centre, we 
have to observe that in its lowest stage of evolution as 
presented to science in the fishes, this type is functionally 
inferior to the invertebrate type, where this reaches its 
highest stage of evolution in the Hymenoptera. 
Emotions . 
Fish display emotions of fear, pugnacity ; social, sexual, 
and parental feelings ; anger, jealousy, play, and curiosity. 
So far the class of emotions is the same as that with which 
we have met in ants, and corresponds with that which is 
distinctive of the psychology of a child about four months 
old. I have not, however, any evidence of sympathy, 
which would be required to make the list of emotions 
identical ; but sympathy may nevertheless be present. 
Fear and pugnacity are too apparent in fish to require 
special proof. The social or gregarious feelings are strongly 
shown by the numberless species which swim in shoals, 
the ^sexual feelings are proved by courtships, and the 
parental by those species which build nests and guard 
their young. Schneider saw several species of fish at the 
Naples Aquarium protecting their eggs. In one case the 
male mounted guard over a rock where the eggs were de- 
posited, and swam with open mouth against intruders. 
The following accounts of t he nidification of certain species 
of fish show that the parental instincts are not unlike 
those which obtain in birds, and are comparable in point of 
strength with the same instincts as they occur in ants, 
bees, and spiders. 
Agassiz remarks 1 that while examining the marine products 
of the Sargasso Sea, Mr. Mansfield picked up and brought to 
him a round mass of sargassum, about the size of the two 
1 Silliman’s American Journal , Feb. 1872. 
