352 Afiimal Life and Intelligence. 



have seen young birds, after some apparent hesitation, 

 peck once or twice doubtfully at such insects. A young 

 baboon with whom I experimented at the Cape seemed to 

 have an undefined aversion to certain caterpillars, which 

 he could not be induced to taste, though he smelt at them. 

 Scorpions he darted at, twisted off the sting, and ate with 

 greedy relish. 



If nudibranchs and other marine invertebrates be pro- 

 tectively coloured, there must be corresponding perceptual 

 powers in the fishes that are thus led to avoid them ; for 

 there seems to be definite avoidance, and not merely in- 

 difference. This, however, might be made the subject of 

 further experiment, not only with fishes, but with other 

 animals. I tried some chickens with currant-moth cater- 

 pillars, to each of which I tied with thread a large looper. 

 Some of them would have nothing to do with the unwonted 

 combination. But one persistently pecked at the looper, 

 and tried to detach it from its fellow-prisoner. Though, 

 on the whole, there was some tendency for aversion to the 

 currant-moth caterpillar to overmaster the appetence for 

 the looper, I was not altogether satisfied with the result 

 of the experiment. But I think that if the protectively 

 coloured larva had been regarded with mere indifference 

 (i.e. neither aversion nor appetence), the appetence for 

 the loopers should have made the chickens seize them at 

 once. 



To return to fishes. It is probably difficult or impos- 

 sible for us to imagine what their constructs are like ; but 

 that they, too, proceed to define them by examination 

 seems to be a legitimate inference from some of their 

 actions. Mr. Bateson says, " The rockling searches [for 

 food] by setting its filamentous pelvic fins at right angles 

 to the body, and then swimming about, feeling with them. 

 If the fins touch a piece of fish or other soft body, the 

 rockling turns its head round and snaps it up with great 

 quickness. It will even turn round and examine uneatable 

 substances, as glass, etc., which come in contact with its 

 fins, and which presumably seem to it to require explana- 



