THE CONQUEST OF THE DRY LAND 221 



shores there is a quaint fish called Perioph- 

 thalmus, with protruding, very mobile eyes. 

 At low tide it skips about among the rocks, 

 hunting small animals, even catching insects. 

 As it clambers on to the exposed, bent-knee- 

 like roots of the mangrove trees, it may be 

 spoken of as a fish that climbs trees. 



There is another tropical fish, known as the 

 Climbing Perch, which has the curious habit 

 of scrambling, by means of its very muscular 

 pectoral fins, up stones, roots, and even the 

 trunks of trees, in search of the insects, grubs, 

 and soft-bodied animals on which it feeds. 



Still more surprising is the habit of a South 

 African fish, called Clarias, which is said to 

 make nocturnal raids on the fields in order to 

 eat the grains of millet. This fish lives in dis- 

 tricts where the rainy season lasts for only two 

 months in the year. The pools that are filled 

 with rain dry up very quickly in the heat of 

 the sun, and all the rest of the year the fish 

 lives its unfishlike life, hiding in damp bur- 

 rows through the day, torpid during the very 

 hot season, but in cooler weather coming out 

 on foraging expeditions at night. Some natu- 

 ralists declare that when this fish is frightened 

 it " screams like an angry cat," but, as no fish 



