648 THE AMERICAN NATURALIST. | [Vor. XXXIX. 
The question of parasitism can, I think, be answered fully in 
the negative. There is nothing in their structure to indicate 
degeneracy, either of the feeding organs, or of the senses with 
which they search for food. Moreover, they have no means of 
attaching themselves to living prey, unless that prey is held help- 
less on a line or in a net. They have neither hooks nor a suck- 
ing disc with which to hang on, and the palatine tooth is too 
short and placed too far back in the mouth to be used for this 
purpose. They can only swim and bite, and I hardly think they 
could make much headway with a powerful free-swimming cod 
or halibut. 
There is one food, however, of which the males are extremely 
fond, and that is the eggs of their own kind. They eat these 
in great abundance, swallowing them whole. One evening, just 
before leaving the laboratory, I found a dead fish in the tank. 
It was a female with eggs almost ready for oviposition, and on 
lifting it the eggs were pressed out. I left them in the tank, 
twenty of them all told, to see what would happen. The fish 
had been fed the day before, and had eaten scantily, so they 
were not hungry, but by morning all but one of the eggs had 
been eaten; a day or so later I found the empty shells cast 
out. The egg is swallowed whole, and its contents slowly 
digested out of it by osmosis, leaving the shell untouched, or at 
most with only a prick in it given in passing over the teeth. I 
have examined several hundred eggs that had been pressed out 
from the intestine, and were in all stages of digestion, from the 
first murky clouding to the breaking and drawing off of the con- 
tents. In none of them was the shell really broken. In many 
of the largely digested ones there was no sign even of the pin- 
hole prick, while in others quite undigested, the perforation of 
the shell was very evident. It must therefore be purely acci- 
dental and in no way necessary to digestion. : 
SENSE PERCEPTION. 
The hagfish has all of the usual sensory nerves and sensory 
un barring the lateral line organs, possessed by the higher 
shes, but they are all in a very primitive condition. It was 
