626 THE AMERICAN NATURALIST. [Voı. XXXIX. 
Dr. Frank McFarland for helpful suggestions ; and to Mr. M. H. 
Spaulding for much practical help. I wish also to thank Dr. 
Michael Guyer, of the University of Cincinnati, for the loan of 
laboratory materials, and to express my obligations to my sister 
Louise for the very excellent and accurate drawings from which 
the illustrations for Fig. ı and 2 were made. 
The Myxinoid upon which the following observations were 
made, is the common hagfish of the Pacific coast, Bdellostoma 
dombeyi Lac. It is found in exceeding abundance in the Bay of 
Monterey, where it is a great pest to the fishermen. It is 
caught both with hook and line, and in traps. Those caught 
on hooks do not live long in captivity. Instead of being hooked 
in the jaw as is usual with other fish, Bdellostoma usually swal- 
lows the baited hook whole, and is thus hooked through the head 
or the body wall, hence the esophagus and stomach are more or 
less torn in extracting the hook. Even under most favorable 
conditions I have not found those caught on hooks to live 
more than a few hours in aquaria. The traps used by the 
fishermen in catching hagfish, are large wicker baskets, loosely 
woven, resembling lobster pots. A quantity of bait, usually 
pieces of squid or sardines, is put inside, and the trap sunk 
over night. In the morning it may contain anywhere from 
twenty-five to a hundred fish, mostly medium size, with a few 
small and several large individuals. The largest hagfish are not 
caught in the traps, as the meshes of the baskets used are too 
small for them to pass through. 
The aquarium, in which I kept them, was a wooden tank, 
about six feet long, four feet wide, and two feet deep. It was 
located in the basement of the laboratory, a large, cool room, 
well lighted. The water in the tank was kept about a foot 
deep, the bottom was covered with a thin layer of clean sand, 
and stones were loosely piled in one corner to furnish hiding 
places. Four streams of fresh salt-water, coming from glass 
pipettes, with a length of stream varying from two to four feet 
between the glass and the surface of the water, played con- 
stantly into the tank, supplying fresh, well aérated water. 
Here the colony lived throughout the summer. Although some 
two hundred and fifty fish were thus kept under observation, 
