FISH AND THEIR NESTS 37 
temperature of the water, the salmon fry hatch 
out. 
Few fish prove more devoted parents than 
the American bow-fin. At the approach of 
the spawning season the males and females 
pair off and resort to the shallow waters of 
their habitat for the purpose of preparing a 
nursery for their prospective family, a circular 
clearing being made amidst the rushes and 
reeds by breaking the stems asunder, or by 
biting through them with their sharp teeth. 
A shallow depression is then formed in the 
ground in the centre of the clearing, wherein 
the female deposits her eggs to the number of 
several thousand. The ova, which are quite 
small, develop very rapidly, the period of 
incubation being about seven or eight days. 
The male watches over the eggs and takes 
charge of the fry when they are hatched, 
keeping the latter together just as a shepherd’s 
dog herds a flock of sheep. 
The bow-fins, which feed upon insects and 
crustaceans, as well as upon other fish, are 
capable of living out of water for several hours 
on end. 
Of the two sexes the male grows to a length 
of about eighteen inches, while the female 
measures about twenty-four inches long. 
The eel-like Gymnarchus , one of the African 
