INTRODUCTION. XXV 



largest quantity of ova, and the range of the influence of the 

 male fluid is enormously increased by diffusion in water. The 

 adhesive nature of the surface of each egg supplies the means 

 of attachment to any of the various substances near which it 

 may happen to be left ; and the time required for the appear- 

 ance of the young fish is very variable, depending upon the 

 species, the season, and its temperature. The young fish is 

 first apparent as a line wound round the central vitelline por- 

 tion of the egg, and ultimately escapes by rupturing the ex- 

 ternal capsule with its tail. 



Considerable attachment is often exhibited between the 

 parent fish. Mr. Jesse relates that he once caught a female 

 Pike during the spawning season, and nothing could drive 

 the male away from the spot at which the female disappeared, 

 whom he had followed to the very edge of the water. In 

 some species this attachment is not confined to the season of 

 spawning. A person who had kept two small fishes together 

 in a glass vessel, gave one of them away ; the other refused 

 to eat, and showed evident symptoms of unhappiness till his 

 companion was restored to him. Some few species show also 

 an attachment to their young, and even watch and defend 

 their own spawn. I shall confine myself to a notice of two 

 British examples. Pennant says of the River Bullhead, 

 " It deposits its spawn in a hole it forms in the gravel, and 

 quits it with great reluctance." I have also been favoured 

 by an excellent observer with the following notice on the 

 same fish : " It evinces a sort of parental affection for its 

 ova, as a bird for its nest, returning quickly to the spot, and 

 being unwilling to quit it when disturbed." It is believed 

 also of the Lump Sucker, that the male fish keeps watch over 

 the deposited ova, and guards it from every foe with the 

 utmost courage. If driven from the spot by man, he does 

 not go far, but is continually looking back, and in a short 

 time returns. 



