102 



with several kinds of food. It was not till some small crabs 

 were put into the tank that it suddenly awoke to activit3^ It 

 instantly seized these animals in its capacious mouth, swallowed 

 them rapidly, and almost at once resumed its sphynx-like 

 attitude. Almost all fish, whatever their natural or usual food 

 may be, will after a time take the food offered them, but this 

 fish was never observed to take anything but crabs. It is an 

 example of specialisation in a group of fishes, which usually 

 lead a free life, are powerful swimmers, and are ready to take 

 almost any food. Other kinds of " Rock Cod " (Epinephalus, 

 Serranus, etc.) are readily caught by hook and line with 

 ordinary bait, but this kind seldom. 



Paarde-visch or Horse-fish {Agriopus, 3 species). 



The genus Agriopus is peculiar to the Southern Hemisphere. 

 At the Cape it is represented by three species — A. torvus, 

 A. spinifer and A. verrucostis. The first is much larger than 

 the others, and is one of the most striking inhabitants of the 

 aquarium. It has a very fierce and forbidding aspect, which 

 the original describer indicates by the specific name " torvus," 

 savage or fierce. It has this same aspect in the tanks and visit- 

 tors frequently express concern for the safety of smaller fish 

 in its company. Its name and appearance are, however, a 

 libel on its true character. It is one of the quietest and most 

 harmless of fish, as well as the laziest. It swims slowly to and 

 fro in the tank, occasionally resting, sometimes almost on its 

 side, or leaning against a rock. The Klip-fish on occasions 

 find it a soft and convenient resting place, for it is devoid of 

 scales. It sometimes yawns, when its appearance is truly 

 terrifying, the large mane-like dorsal fin with its strong spine 

 being stiffly erected, and its protruding mouth widely opened. 

 It has large, closely-set eyes and a high forehead. Its colour 

 is dark brown, usually with a few longitudinal lateral white 

 bands which sometimes disappear. At other times faint 

 vertical stripes may be seen. 



It is not easily startled and takes no interest in other fish, 

 quietly moving off when interfered with. It, however, takes 

 a great interest in small moving things, especially small crabs. 

 If one of these is introduced into the tank it swims up to it 

 with a sort of clumsy haste and proceeds to scrutinise it closely, 

 often twisting its body and head as if making a calculation, 

 all being done very deliberately and with no attempt at con- 

 cealment or strategy. The next thing observed is the absence 

 of the crab, which has been seized by a sudden protrusion of 

 the mouth of the Horse-fish at a distance of about an inch. 



