Instincts, Habits, and Adaptations 43 
many other features of mimicry serve as concessions to the en- 
vironment. 
Each kind of fishes has its own ways of life, fitted to the con- 
ditions of environment. Some species lie on the bottom, flat, 
as a flounder, or prone on their lower fins, as a darter or a stone- 
roller. Some swim freely in the depths, others at the surface 
of the depths. Some leap out of the water from time to time, 
as the mullet (Mugzl) or the tarpon (Tarpon atlanticus),. 
Flight of Fishes.—Some fishes called the flying-fishes sail 
through the air with a grasshopper-like motion that closely imi- 
tates true flight. The long pectoral fins, wing-like in form, 
cannot, however, be flapped by the fish, the muscles serving 
Fic. 29.—Catalina Flying lish, Cypsilurus califjornicus (Cooper). Santa Barbara. 
only to expand or fold them. These fishes live in the open sea 
or open channel, swimming in large schools. The small species 
fly for a few feet only, the large ones for more than an eighth 
ofa mile. These may rise five to twenty feet above the water. 
The flight of one of the largest flying fishes (Cypsilurus calt- 
fornicus) has been carefully studied by Dr. Charles H. Gilbert 
and the writer. The movements of the fish in the water are 
extremely rapid. The sole motive power is the action under 
the water of the strong tail. No force can be acquired while 
the fish is in the air. On rising from the water the movements 
