FISHES' EGGS 15 



Next, he seeks the lady of his choice with the purpose 

 of inducing her to lay her eggs in his nest. First, he 

 tries to persuade her, swimming round and round and 

 advancing before her, but should his blandishments fail, 

 he suddenly becomes annoyed, and erecting the spines 

 on his back he endeavours to drive her to the nest with 

 several well-directed nips from his powerful jaws. 



If, during these endeavours to persuade the lady to 

 visit his nest, a second male appears upon the scene, a 

 battle royal ensues. Brilliant in colour and bristling 

 with rage, the jealous fish bite and chase each other 

 through the weeds. At the conclusion of the fight the 

 vanquished combatant, immediately losing his brilliance, 

 slinks off to his own quarters, while the victor, becoming, 

 if possible, still more brilliant in colour, advances to the 

 female stickleback, who has been demurely watching the 

 fray, and without much difficulty persuades her to visit 

 his nest, and deposit her quota of big eggs. 



The nest, when completed, is a tube closed at one 

 end. But whereas the male used to back out when 

 leaving it, the female, after laying her eggs, bores her 

 way through the closed end of the nest, thus converting 

 it into a tunnel. This is a useful provision, for later the 

 male fish aerates the eggs by sending a stream of water 

 through this tunnel with a fanning movement of his 

 pectoral fins. 



When the female fish has laid her eggs, the fickle 

 male drives her away, and, going through the same 

 manoeuvres, induces five or six others to add their eggs 



