244 THE SENSE-ORGANS AND PERCEPTION OF FISHES, 



fisli came up behind it. Sticklebacks and blennies^ on tbe otber 

 band, snatcb pieces from each others' mouths like hens ; so also do 

 eels and other fish which hunt by scent. Conger, in particular, 

 fight lustily over their food ; and though they may hesitate for some 

 time to take a piece of food which is tainted, or a substance of other- 

 wise doubtful scent, yet they bolt it at once if another conger or a 

 crab begins to examine it or pull it away ; afterwards, if need be, 

 they reject it. These remarks illustrate the necessity for caution in 

 making deductions as to the likes and dislikes of fishes from scanty 

 observations. 



It has been mentioned that various fishes differ in their powers of 

 seeing things above or on a level with them, but far more remark- 

 able is the difference in the degree to which they are able to see 

 downwards. Of the fish mentioned above the following were never 

 seen to eat food after it had fallen to the bottom of the tank : — bass, 

 bream, dory, boar-fish, lump-sucker, and pollack. The pollack are 

 particularly interesting to watch in this connection, appearing abso- 

 lutely unable to find objects which have reached the ground. It 

 may be that their vision is such as not to admit of the perception of 

 things below them, or it may be that the whole surface of the bottom 

 is to them indistinct and blurred, or possibly the pi'otruding lower 

 jaws of these fish prevent them from picking up objects lying on the 

 ground, but certainly they never seem to attempt it ; and if they 

 fail to catch worms, shrimps, &c., as they are falling through the 

 water they give up at once. It is to be regretted that the majority 

 of the fishes living at Plymouth are littoral forms, and such as are 

 accustomed to live and feed on the bottom ; for it is likely that there 

 are many other fishes which are similarly unable to find food which 

 is below them. It may be mentioned that, in addition to those given 

 above,it is rarely that mullet or small poutingfind food on the bottom. 

 Pouting of larger size, however, use their pelvic fins for this purpose, 

 as hereafter described. In fact, it is probably exceptional for an 

 ordinary freely swimming fish, which hunts by sight, to seek food 

 which is not in suspension ; for nearly all those that have the power 

 of feeding on the bottom either possess organs of touch, as the 

 gurnard and pouting, or moveable eyes, as the wrasses and pipe-fishes, 

 or else have the eyes peculiarly placed, as the flat fishes and blennies. 



The mode of feeding of the dory and pipe-fishes is sufficiently sin- 

 gular to call for special remark. These animals are both provided 

 with transparent, vibratile membranous fins. In the dory these are 

 caudal, anal, and pectoral, while in the pipe-fishes the pectoral and 

 dorsal only are thus developed. By the oscillation of these the 

 animal approaches its prey without making any general movements, 

 and in fact stalks it. The flattened body of the dory is most in- 



