304 A HISTORY OF FISHES 



hood of their nests ; after a few rounds one gives in and then 

 the victor indulges in a splendid display of colours. . . ." 

 Curiously enough, the colours of the unsuccessful fish become 

 dull as soon as he retires from the combat, and for some time 

 he is the constant object of persecution by his conqueror. 



As a general rule, in those fishes in which courtship and 

 pairing takes place at the breeding season the number of eggs 

 produced by a single female is small or moderate, and these 

 are cared for to a greater or lesser extent by one or both of the 

 parents, generally the father. This parental care may take the 

 form of constructing some sort of nest for the reception of the 

 fertilised eggs, varying from a simple hollow scooped out in 

 the gravelly bed of a stream to a beautiful and elaborate 

 structure, or of some other precautions designed to ensure the 

 safety of the eggs or offspring until they are old enough to take 

 care of themselves. 



The Darters {Etheostominae) , .pretty little fishes of the family 

 Percidae, found in the rivers of eastern North America, congregate 

 together in gravelly shallows at the spawning season, the larger 

 males each selecting a suitable place which they regard as their 

 own domain, repelling with vigour any attempt by a rival 

 male to dispute their claim. Any female entering the domain 

 is allowed to remain, and she constructs a kind of trough with 

 her body into which she sinks as the eggs are extruded. These 

 are promptly fertilised by the male, and being covered with a 

 sticky substance, they adhere to the stones. The extent to 

 which the Salmon and Trout care for their offspring is almost 

 equally primitive, and has been already described. Dr. Semon 

 has recorded the breeding habits of a species of Cat-fish (Arius) 

 found in the Burnett River of Queensland, in which a further 

 advance in the protection of the prospective family is exhibited. 

 The nests of this fish consist of circular excavations, about 

 twenty inches in diameter, scooped out in the bed of the river. 

 The fertilised eggs are covered with a layer of large stones, but, 

 this being done, the parents take no further interest in the 

 fate of their offspring. Many of the North American Cyprinids, 

 known as Chubs and Shiners, construct somewhat more elabor- 

 ate nests composed of large heaps of stones, some of which may 

 weigh nearly eight ounces, but the eggs are here again left to 

 the mercy of physical conditions, to say nothing of predaceous 

 fishes. 



The fresh- v/ater Sun-fishes {Centrarchidae) scoop out a shallow 

 basin-like nest, from the bottom of which all pebbles are carefully 



