FISHES. 145 



and alacrity, Iraiit for suitable materials for the construction 

 of their nests. These materials consist of small vegetable fibres 

 and other substances of the like kind. The nests, when com- 

 pleted, vary somewhat in shape, but they may be described as 

 rather like a hedge-sparrow's nest, having a top and a hole in 

 the side for a door. They have also been occasionally likened 

 to a flattened hay-cock, a tiny barrel, or a lady's mufE. They 

 are generally about IJin. in length. The building materials 

 are kept together by a kind of mucus or cement, which comes 

 from the fish as they draw their bodies over and about the 

 nest. Sometimes if the fibres and other substances are not 

 heavy enough to keep in their proper positions until the 

 cementing operation is completed, the clever Httle nest-builders 

 will weight them down with sand or minute particles of gravel, 

 which they will collect in and discharge from their mouths. 

 Such are the energy and skill of the little fish that the nests 

 are frequently finished within a few hours. Immediately they 

 are completed, the fish set out in search of wives. And should 

 these gaily-coloured courtiers meet one another while on this 

 errand there is sure to be a fight, especially if they happen to 

 make up their minds to pay their respects to the same lady 

 Stickleback. As they quickly make preparations for the 

 encounter their colours grow more brilliant than ever, while 

 the coveted little female retires demurely to one side and 

 becomes a silent, though not an uninterested, witness of the 

 battle. The fish charge furiously at one another, and then, 

 if no great harm has been done, continue to swim round and 

 round, trying to bite with their strong mouths or to pierce 

 each other with their sharp lateral or dorsal spines. So the 

 fight goes on until one is obliged to give in. The poor defeated 

 fish — one feels so sorry for him — loses at once his gallant 

 bearing, and swims away with quickly-fading colours, while the 

 conqueror becomes, if possible, more gorgeous than ever as he 

 claims the gentle spectator of the fray as his lawful prize. 

 With all the address of which he is capable he persuades her 

 to inspect the little nest which he has buUt. He then pressingly 

 invites her to enter the door, in order that she may lay her 

 eggs within. In a few minutes the eggs are laid, and the fish, 



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