No. 465.] STUDIES OF MYXINOIDS. 655 
ovary, the fish, although it had already been beheaded, squirmed 
so that it was almost impossible to operate. The body was cut 
in half in the hope of quieting it, by cutting through the spinal 
cord, but both halves squirmed as vigorously as ever. i 
The most remarkable case of all was that of a young hagfish 
eleven and a half inches long. It was beheaded before noon. 
At five in the afternoon its body was opened its entire length. 
As soon as the instrument touched it, it squirmed vigorously, 
tying itself into a knot. In ten minutes the examination was 
over, it was thrown into the ocean, and my attendant at once 
reported that on touching the water it swam away. It would 
be interesting to know how long its swimming continued. 
In contrast with the spinal cord, the life of the brain cells is 
short, particularly those in the fore part of the brain. When 
the fish were beheaded, the brains had to be removed and put 
into the kiling fluid within an hour or they were valueless for 
histological work. 
REPRODUCTION. 
The hagfish have only one reproductive organ, a peritoneal 
fold hanging from the roof of the right half of the body cavity. 
When the eggs or sperm are ripe, the organ fills the entire 
right side of the body cavity, but after discharge, it is all 
absorbed except for a small matrix at the caudal end. In this 
stage the sex of the organ is distinguishable only by histological 
examination. It appears as a small thickly gathered frill, the 
outer edge of which holds a multitude of tiny spheres, the 
undeveloped ova or sperm spheres respectively. As the hag- 
fish has no external marks of sex, in this stage it requires a 
microscope to distinguish between male and female animals. 
As the process of ripening proceeds, the frill becomes thicker, 
and extends cephalad, the spheres becoming more numerous 
and the ova growing ovoid in shape. The frill may extend pos- 
sibly one third of the way cephalad, before its edge becomes 
thicker, or the sex apparent. I cannot state positively at what 
length this occurs, but by the time it has grown halfway along 
the cavity, the edge is at least double in thickness what it was 
