324 Account of the Nest of Sticklebacks. 



exerts himself to consolidate his structure, it is necessary 

 that he should arrange it suitably for the purposes for which 

 it is intended. Accordingly he never fails to reserve an 

 opening very neatly and regularly circumscribed, into which 

 he often thrusts his head and even a large part of his body, 

 in order to press out the walls and keep the interior cavity 

 sufficiently dilated that the female may have sufficient room 

 to lay her eggs in it : of these eggs he afterwards becomes 

 the courageous and indefatigable defender. 



When the construction of the nest is sufficiently advanced 

 to receive the ova, the male darts forth, in a state of agita- 

 tion, into the middle of a group of females, in order to attract 

 the attention of one about to deposit her spawn and to offer 

 her an asylum for her offspring. She easily distinguishes 

 the ordinary males ; for they wear the rich livery of love, and 

 are adorned with the liveliest colour. Accordingly when 

 she sees him advance, she becomes eager, goes up to him, 

 slides along his back, and, by a series of coquettish move- 

 ments, and mutual allurements, seems to express to him 

 that she is ready to follow him. Then the male, understand- 

 ing this mysterious language, hurries towards his nest, as if 

 to point out the way, thrusts his head into the gaping aper- 

 ture, eagerly enlarges it to facilitate her entrance, then gives 

 place to the female, who, by entering, seems to accept his 

 invitation, She enters within it, leaving nothing to be seen 

 without but the extremity of her tail, which lies across the 

 opening by which she entered. She remains there two or 

 three minutes, during which her convulsive motions indicate 

 the efforts she is making to extrude her eggs ; then she darts 

 out, pale and discoloured, after having pierced through the 

 nest, so that, although it had only one opening before the 

 entrance of the female, it has two after she has deposited 

 her ova. 



While she is engaged in this operation, the male, whose 

 changing colours and animated motions express his increas- 

 ing agitation, appears to be thrown into a kind of paroxysm, 

 and seems desirous to hasten the moments when he may 

 enter in his turn. He assists the female, rubs her with his 

 snout, as if to encourage her, and when she has accomplished 



