THE SENSE-ORGANS AND PERCEPTION OF FISHES. 245 



conspicuous when seen from in front, as is that of the pipe-fishes 

 when seen end-on. The dory feeds on small fish, working up to 

 them in this way very slowly and with precision, like a man working 

 up to game in open country where there is no cover. On getting 

 within range, which is some inches from the prey, the immense pro- 

 trusible jaws are shot out, and the fish is drawn back with them into 

 the mouth. When the dory sights his prey the whole aspect of the fish 

 changes. The curious brown markings on the body, which are at 

 times scarcely visible, blush up and become dark. Of these the 

 most conspicuous is a wide dark band passing down the middle of 

 the nose and continuing between the jaws ; this dark stripe gives the 

 fish a most singular appearance when seen from in front. In the 

 case of the pipe-fish, which feeds largely on small shrimps, the face 

 is drawn out into the well-known pipe-like process which is gradually 

 pushed right up to the victim, who would be alarmed and escape at 

 the approach of a more clumsily organised fish. During this pro- 

 ceeding the pipe-fish frequently comes forward on its ventral surface. 



None of these sight-hunting fishes while living' in the tanks appear 

 able to see their food by night, or even in twilight ; worms thrown 

 in after dark fell through the water unnoticed. It did not appear 

 that this was due to reluctance on the part of the fish to eat by night, 

 for on some occasions pollack took worms by night when the light of 

 a bull's eye was turned on them so that the fish could see them. 

 In view of this fact it would be interesting to see if fishes would 

 take an object made luminous with Balmain's luminous paint or other- 

 wise. I made experiments with pieces of india-rubber and with 

 twisted glass tubes filled with luminous paint and sealed up, but 

 none of the fish took any notice of them. Perhaps, however, such 

 fish as mackerel might be attracted by similar objects trailed along 

 in the open sea by night ; for so many of the animals which are 

 preyed upon by fishes are phosphorescent, that it is likely that some 

 at least are accustomed thus to recognise them. 



In view of the brilliant colours which are so common among marine 

 animals it would be highly interesting to get some idea of the colour 

 sense of fishes, but so far my results have been chiefly negative. 

 In the first place I endeavoured to find out if light of any particular 

 colour were invisible to soles and other nocturnal fish which, as 

 already stated, swim about in the dark, but hide themselves when a 

 light is turned on them. My experience was that their behaviour did 

 not appreciably differ whether the light was red, blue, or green ; and 

 in fact they (eels and soles) seemed to be conscious of and to avoid 

 coloured light almost as much as plain light. On the other hand, the 

 pupil of Eledone contracts much less for red light than for other 

 colours ; and the larvae of the lobster, which swim towards a light, 



