I JO A NATURAL HISTORY OF THE SEAS 



it is not always the case. Many of the " eye-spots " seen 

 in certain fishes ate constant as regards position and vary 

 only in intensity. Though explanations must perforce 

 be conjectural, it is suggested with some reason that these 

 serve as " recognition marks " which aid the shoal to keep 

 together. These marks are often more pronounced in the 

 male fish and become greatly intensified by excitement, 

 as produced for instance by the prospect of food or the 

 sudden appearance of a hated rival. Such intensification 

 of markings is very notable in some of the fish to be seen 

 in the Regent's Park Aquarium, and eminent authorities 

 have suggested that their vividness serves to attract or 

 hypnotise the small fish or prawn which the bearer hopes 

 to engulf. 



Certain fish, like the Trigger Fishes, which are known 

 to be poisonous, undergo marked colour changes when 

 threatened, and it is possible that such changes spell 

 " danger " in the manner of the skunk's upraised tail or 

 the cobra's expanded hood. 



Many fish, the Common Cod (Gadus morrhud) for example, 

 are literally living trawls, and the stomach of a Cod Fish 

 of normal dimensions has yielded, besides scores of crabs, 

 small fish and sea worms, stones 4 lbs. or more in weight. 

 The palm for swallowing feats, however, goes to the 

 so-called " Swallower " (Chiasmodon ntger\ a fish from the 

 abyss, which has so distensible an interior that it can, 

 and often does, engulf active fishes of five times its own 

 length and many times its weight. The degenerate 

 abyssal Eels, of the genus Eurybarynx, must be equally 

 voracious since the mouth of one such fish measures 

 more than a quarter of the creature's entire length. 



