FISH NEST- BUILDING. 245 



multitude of air-bubbles like little pearls clinging all over his 

 body. 1 



Again, in detailing Mr. Baker's observations on the 

 three-spined stickleback, published in the Philosophical 

 Transactions, this author says : 



It has been remarked that after the deposition of the eggs 

 the nest was opened more to the action of the water, and the 

 vibratory motion of the body of the male fish, hovering over its 

 surface, caused a current of water to be propelled across the 

 surface of the ova, which action was repeated almost continu- 

 ously. After about ten days the nest was destroyed and the 

 materials removed ; and now were seen the minute fry flutter- 

 ing upwards here and there, by a movement half swimming, 

 half leaping, and then falling rapidly again upon or between 

 the clear pebbles of the shingle bottom. This arose from their 

 having the remainder of the yelk still attached to their body, 

 which, acting as a weight, caused them to sink the moment the 

 swimming effort had ceased. Around, across, and in every 

 direction the male fish, as the guardian, continually moved. 

 Now his labours became more arduous, and his vigilance was 

 taxed to the utmost extreme, for the other fish (two tench and 

 a gold carp), some twenty times larger than himself, as soon 

 as they perceived the young fry in motion, continuously used 

 their utmost endeavours to snap them up. The courage of the 

 little stickleback was now put to its severest test ; but, nothing 

 daunted, he drove them all off, seizing their fins and striking 

 with all his strength at their heads and at their eyes. His 

 care of the young brood when encumbered with the yelk was 

 very extraordinary ; and as this was gradually absorbed and 

 they gained strength, their attempts to swim carried them to a 

 greater distance from the parent fish ; his vigilance, however, 

 seemed everywhere, and if they rose by the action of their fins 

 above a certain height from the shingle bottom, or flitted beyond 

 a given distance from the nest, they were immediately seized in 

 his mouth, brought back, and gently puffed or jetted into their 

 place again. The same care of the young, bringing them back 

 to their nest up till about the sixth day after hatching, has 

 been remarked by Dr. Ransom in the ten-spined stickleback 

 (G. pungitius). 1 



The well-known habit of the lophobranchiate fish, of 

 ' Ibid. 



