40 MR. ¥. DAT ON THE 



across the surface of the ova, which action was repeated almost 

 continuously. 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 bhe 

 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. ISTow 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, so 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 imme- 

 diately 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. Eansom in the 10-spined 

 Stickleback, G. pungitius. 



The usual time for the Lamprey, Petromyzon fluviatilis, leaving 

 the sea, which it is annually seen to do, in order to spawn, is 

 about the beginning of spring ; and after a stay of a few months 

 it returns again to the ocean. Their preparation for spawning is 

 very peculiar: their manner is to make holes in the gravelly 

 bottoms of rivers ; and on this occasion their sucking power is 

 particularly noticeable, for if they meet with a stone of conside- 

 rable size, they will remove it and throw it out. Their young 

 are produced from eggs ; the female remains near the place where 

 they are excluded, and continues with them till they come forth. 



* Warrington, " On the Habits of the Stickleback," Ann. & Mag. Nat. Hist 

 1855, xvi. p. 330. 



