Mr. R. Waririgtbn on the Habits of the SticklebacJc. 331 



The position selected by the male fish for the constniction of the 

 nest was between two plants of Vallisneria spiralis, at the point 

 where the leaves spring from the root, and directly in front of a 

 fragment of limestone which rose behind the plants and acted 

 as a protecting background to the position. The nest being all 

 prepared, exactly as before described, although by another indi- 

 vidual, the eggs were deposited, I presume, during the night of 

 May 8th : this was judged of, not from observance of the act of 

 spawning, but from the altered appearance of the female fish 

 evidencing that she had shed her spawn, from the immediate 

 change made by the male fish in the arrangement of the mate- 

 rials forming the nest, and, likewise, the violent repulsion of 

 the female from the neighbourhood of its position, to which pr0^ 

 viously he had been as assiduous in driving her. '»^ 



From this period the nest was opened more to the action of 

 the water, and the vibratory motion of the body of the male fish, 

 while hovering over its surface, caused, as before described, a 

 current of water to be propelled across the surface of the ova ; 

 this action was repeated almost continuously. The apparent 

 luminosity of the body, if I may so term it, also decreased, and 

 in this state all continued without change until the 18th of May, 

 making a period of ten days. After this date the whole nest 

 was destroyed, and the materials of which it had been composed 

 thrown aside, with the exception of a few wiry stems of a de- 

 cayed water moss, and a space cleared around the spot of about 

 3 inches in diameter ; the mud or sand at the bottom being 

 carefully removed with its mouth and carried in this manner to 

 some distance, leaving the rounded stones of the gravel clean 

 and free from any obstruction around them. '/_ 



Watching carefully for a short time, to understand what all 

 this busy alteration indicated, I at last had the pleasure of ob- 

 serving, by the aid of a long-focused pocket-lens, some of the 

 young fry, — of course most minute creatures, fluttering up- 

 wards here and there, by a movement half swimming, half leap- 

 ing, and then falling rapidly again upon or between the clean 

 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 all this space above mentioned, and across it in every 

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

 now his labours became still more arduous than they had been 

 before, and his vigilance was taxed to the utmost extreme, for the 

 other fish, three of them some twenty times larger than himself, 

 as soon as they perceived that the young fry were in motion, used 



