638 THE AMERICAN NATURALIST.  [Vor. XXXIX. 
cans, thirty or forty were sick on arrival, but the next morning 
two only were dead, and all the rest in fine condition. It is 
noticeable that the young ones have, as a whole, more power of 
resistance than the old ones, for they would arrive fresh, as 
though just from the depths of the bay, no matter how sick 
many of the older ones were. 
There is one unfailing test of the general condition of the 
hagfish : its geotropic reaction. When well and at rest, it is 
invariably coiled up more or less tightly, either in a spiral by 
itself (Fig. 2) or in and out among the rocks. Even if the fore 
part of its body lies free and sinuous, the tailis coiled. But if 
exhausted or sick, the coil straightens out, and it lies in a cres- 
cent form. The sicker it is, the straighter it becomes, and 
when dead it lies entirely straight, 
The hagfish can live out of water without injury for a great 
many hours if kept in a cool, damp place. I often found on 
visiting the tank in the morning, that one or more of the 
smaller fish had found the water outlet while swimming in the 
night, and had slipped to the floor. They would be tightly 
coiled on the cool, moist cement floor, and were as agile and 
active there as in their native element. 
There is one condition, however, that the fish cannot endure: 
a rise in temperature. The water on the surface of the Bay of 
Monterey averages in summer 64? F. or 17.7? C. What it is 
at a depth of two hundred feet, I do not know, nor how cold it 
gets in winter. But the air at Monterey is never so cold as to 
kill palms or heliotrope, so the water cannot become very cold. 
The water in the tank in which I kept the fish averaged 22? C., 
and in that they throve. On a warm sunny morning, I placed 
two young hagfish in a tank about three feet long by one foot 
wide, covered them with about five inches of fresh salt water at 
ae Gu and placed the tank by a window, where the sun shone 
directly into half of it, leaving the other half of it shaded. 
Under the heat of the sun the water in the tank rose gradually 
to 30° C. As the water became warmer, the fish grew very 
restless and languid, swimming constantly, not rapidly as usual, 
but with a slow, jerky movement as though seeking to escape 
the warm water. At the end of two hours and a half one of 
