£46 BULLETIN OF THE UNITED STATES FiSH COMMISSION. 
Most of the forms in the list above are more or less nocturnal animals, but they 
differ much in this regard. The part attributed to the sense of sight and smell in 
Bateson’s studies is so similar to my own conclusions in many respects that it seems 
fitting to quote the greater part of his description, especially since the species 
observed by us are in all cases different. He says: 
None of these fishes ever start in quest of food when it is first put into the tank, but wait for an 
interval, doubtless until the scent has been diffused through the water. Having perceived the scent 
of food, they swim vaguely about and appear to seek it by examining the whole area pervaded by the 
scent, having seemingly no sense of the direction whence it proceeds. Though some of these animals 
have undoubtedly some visual perception of objects moving in the water, yet at no time was there the 
slightest indication of any recognition of any food substance by sight. The process of search is equally 
indirect and tentative by day and by night, whether the food is exposed or hidden in an opaque vessel, 
whether a piece of actual food is in the water or the juice only, squeezed through a cloth, and, lastly, 
whether (as tested in the case of the conger and the rockling) the fish be blind or not. * * * The 
perceptions, then, by which these animals recognize the presence of food are clearly obtained by 
means of the olfactory organs and apparently exclusively through them. I was particularly surprised 
to find no indication of the possession of such a function by the sense organs of the barbels and lips or 
by those of the lateral line. As has been already described, the pelvic fins and barbels of the rock- 
lings ( Motella ) and the lips, etc,., of most fishes bear great numbers of sense organs closely comparable 
in structure with the taste buds of other vertebrates. No one who has seen the mode of feeding of the 
rockling or pouting ( Oadus hcscus) can doubt that these organs are employed for the discrimination of 
food substances; but the fact already mentioned, that the rockling in which the olfactory organs had 
been extirpated did not take any notice of food that was not put close to it, points to the conclusion 
that they are of service only in actual contact with the food itself. 
Bateson gives also a considerable list of fishes which he has observed to get their 
food chiefly by the sense of sight, and he is doubtless correct in asserting that the 
majority of fishes belong to this class. None of these sight-hunting fishes while living 
in his tanks appeared able to see their food try night, or even in twilight. None of 
the fishes which he enumerates as belonging to this class showed symptoms of interest 
when the juice of food substances was put into the water, and other evidence is 
brought forward to show that the sense of smell plays little or no part in helping 
them to discover their food. 
1 have not studied any of the species mentioned by Bateson, but for the forms 
studied by me, which have an extensive supply of terminal buds on the outer skin, 
1 fully confirm most of the statements quoted above, save that in determining the 
part played by sight I did not blind any of my fishes and save that the statement 
that in fishes of his first group “at no time was there the slightest indication of any 
recognition of any food substance by sight” is strictly true of none of my fishes 
except Ameiurus, though in some of the other cases it is approximately true. 
The only important respect in which my observations are not in harmony with 
those of Bateson is in connection with the part played by the sense of taste in some 
of these types of fishes. 1 have studied the gustatory reactions of fishes closely 
allied to the rockling and having the same arrangement of terminal buds on the barb- 
lets and pelvic fins, and am convinced that Bateson’s failure to get clear gustatory 
reactions from these organs was due to the insufficiency of his methods of experi- 
ment rather than to the absence of the function. In general, it may be stated that 
the part played by the gustatory reflex in the case of fishes having an extensive sup- 
ply of terminal buds on the outer skin is of vastly greater importance than Bateson 
appears to have recognized. 
