242 Mr. A. Hancock on the Nidification of 



species, a few specimens should be placed in confinement about 

 May or June ; and then all their movements can be narrowly 

 watched and accurately observed. Care must be taken, however, 

 that they be left unmolested, and that their new abode resemble, 

 as much as possible, their usual haunts. I have lately had an 

 opportunity of noticing the habits of this fish, during the breed- 

 ing season, under the above favourable conditions. 



We have, for some time past, kept a glass trough filled with 

 aquatic plants and animals ; the bottom of this vessel is covered 

 with mud, and the rock-work, piled up in the centre, is over- 

 grown with a delicate hair-like Conferva ; a few floating plants 

 spread over the surface of the water, and innumerable Entomo- 

 straca and other small Crustaceans, as well as various animal- 

 cules, swarm in all parts ; the minute, but deadly, poison-armed 

 Hydra also prevails where food is so plentiful ; and a solitary 

 individual of the great water beetle, Dytiscus marginatus, rambles 

 over its watery domain, lord and master of all. Several of the 

 freshwater Mollusca also people the trough, which on the whole 

 has much the appearance of a miniature pond. Into this new 

 home were put four or five sticklebacks last May ; and they, at 

 once, made themselves perfectly at ease. One, without the least 

 hesitation, took possession of a certain spot, which it guarded 

 with the greatest pertinacity, attacking vigorously any of its 

 companions that might happen to approach the chosen locality. 

 The beetle too, which sometimes came slowly paddling by, was 

 pounced upon and unceremoniously tumbled over ; but secure 

 within his scaly armour, as the knights of old, he little heeded 

 the onslaught of his naked assailant ; so overpowering all oppo- 

 sition he scrambled onward in his undeviating path. 



This fish was rather small, had the throat of a bright red 

 colour, and the eyes of a brilliant bluish green. At first, all the 

 others were pale ; but, in the course of a few days, one of them 

 gradually assumed the rich hues of that just described, and soon 

 afterwards it also became attached to a spot, taking up its abode 

 in one of the corners of the trough. On examining attentively 

 the two selected localities, a nest was found in each, composed 

 of a collection of delicate vegetable fibres, resting on the bottom 

 of the trough, and matted into an irregularly circular mass, 

 somewhat depressed, and upwards of an inch in diameter ; the 

 top being covered over with the same materials, and having, in 

 the centre, a large hole. The fishes scarcely ever strayed from 

 their nests, but were constantly on guard, defending or repairing 

 •them ; they were perpetually prying into the hole at the top 

 and thrusting their heads right into it. On one occasion, one 

 of them entered by this hole, and slowly forced itself right 

 through the side of the nest : as it gradually moved onward, its 



