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- 
hike 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 
