" PERFECT-MOUTHED " FISHES 225 



The Bow-fin is provided with a large, cellular air-bladder which 

 serves as a lung, and the fish is in the habit of rising frequently 

 to the surface of the water (especially when this is at all foul) to 

 take in fresh supplies of air. When acting in this way it is said 

 to emit a bell-like sound, due to the escape of the exhausted air 

 from the air-bladder. 



" In the breeding season, which lasts from the beginning of May 

 until June, the fish makes its way from the deeper water, where 

 it has remained sluggish during the winter, to the spawning ground. 

 This is usually at the swampy end of a lake, where there is an 

 abundance of aquatic herbage intersected by channels of clear 

 water. There the fish is said to circle round until the soft weeds 

 and rootlets are bent and crushed aside, so as to leave an area 

 having the appearance of a crude form of nest, in which the eggs 

 are deposited. They may be found in enormous numbers adher- 

 ing to the leaves and rootlets of the weedy home. After oviposition 

 the male remains on guard until the young are hatched out, when 

 they appear to leave the nest in a body, still under the protection 

 of the watchful parent. At all events, a little later the male has 

 been observed to be accompanied by a swarm of young fry, which 

 he keeps together by circling round them." l 



To give an exact definition of the Teleostei in a few words is 

 Tactically impossible. To this immense division belong the great 

 majority of living fishes a vast host which varies to an enormous 

 degree in size, in form, in colour, and in habits. It includes 

 the snake-like Eel, the rotund Globe Fish, the swift and 

 graceful Salmon, and the flat and sluggish Plaice, to mention 

 only a few varieties ; while others are of such extraordinary and 

 grotesque shapes that a casual observer might well imagine that 

 they were not fishes at all. Although the majority are clad in 

 sombre hues, some rival the tropical birds in the brilliance of their 

 colour ; even in temperate waters many may be seen most beauti- 

 fully and delicately tinted, but, as usual, the most gorgeous species 

 are dwellers in the warmer parts of the globe, the most vividly 

 coloured fish being found in the tepid waters among the coral 

 reefs. 



Roughly, the Teleostei may be described as fishes that have a 

 bony skeleton, and are covered with flexible scales more or less 



1 T. W. Bridge, Sc.D., F.R.S. 

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