FEEDING REACTIONS OF AMBYSTOMA 53 
ments. On the other hand, it is quite apparent in many in- 
stances that the animals respond before the meat is detected by 
sight. A small inedible object held quietly in the water may 
be approached as promptly as a bit of meat if in the normal 
movements of the animals it falls within their range of vision. 
They approach and may even seize it, but do not manifest as 
great interest in it as in an edible object. Obviously the dis- 
crimination between edible and inedible objects involves the ol- 
factory sense. 
These general observations suggest that the sense of sight 
plays a very important part in the approaching reaction, and 
that not uncommonly this reaction is followed more or less 
spontaneously by the seizing reaction. The determination of 
the relative importance of the sense of sight and the olfactory 
sense in the feeding reactions requires more exact experimental 
data. The results of experiments designed to throw some light 
on this problem are recorded below. 
Twenty-two hungry larvae were placed in an aquarium (18 
x 28 inches) containing water three inches in depth over a 
bed of sand. A bit of meat was held quietly near the center 
of the aquarium and approximately one inch below the surface 
of the water until it was seized. Each animal which seized a 
bit of meat was removed from the aquarium before the next 
trial was made in order that the same animal might not seize 
more than one bit of meat. Twenty trials resulted in an average 
interval of 60.5 seconds during which a bit of meat was held in 
position before it was seized. Several hours later, with all of the 
animals in the aquarium, bits of meat were offered in the same 
manner, but none of the animals were removed during the en- 
tire series of trials. Under these conditions twenty-four trials 
resulted in an average interval of 27.1 seconds during which 
a bit of meat was held in position before it was seized. In this 
experiment some of the animals responded much more quickly 
than others, and seized more than one bit of meat. Indeed 
some of them responded more promptly and more vigorously 
after having seized a bit of meat than when they were attract- 
ed by the meat for the first time. A bit of meat suspended by 
a thread was now moved slowly to and fro along the midline 
of the aquarium approximately one inch below the surface of 
