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 occm-s 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 the nidification of certain species 

 of fish show that the parental instincts are not unhke 

 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 ^ 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. 



