No. 420.] HISTORY OF STICHOSTEMMA., 979 
number of them must reach deeper water, where they continue 
to live beneath the ice during the winter. The lagoon is twelve 
to fifteen feet deep in many places, and no freezing occurs in 
the deeper parts. There is no evidence that the worms are 
capable of enduring actual freezing. After the first appear- 
ance of ice in the lagoon I have chopped out and thawed 
masses of the vegetation in which the worms had been abun- 
dant a few days before, but which were frozen solidly into the 
ice when removed. In aquaria and jars prepared from these 
no worms ever appeared. During the winter of 1899-1900 
a part of the lagoon remained open until about the middle of 
January, although the weather was cold and the remainder 
was covered with several inches of ice. Up to this time the 
worms were found here in abundance. Later this area was 
covered with ice a foot or more in thickness, and the bottom 
was also frozen in the shallower parts, and at this time no 
worms were obtained from the region. 
It is possible that the worms burrow into the mud, but sam- 
ples of the mud taken at various times during the winter have 
never yielded a specimen. I have been unable to examine fully 
the deepest parts of the lagoon, but believe that the animals 
remain more or less active there during even the colder months. 
The worms reappear near the shore in large numbers very 
soon after the ice begins to melt. In 1900 the lagoon was 
covered with from twelve to sixteen inches of ice on March 20. 
By March 26 the ice had melted along the shores, leaving some 
two or three feet of open water from six inches to a foot in 
depth. At this time large numbers of worms were found in 
this open area, nearly all of them large specimens with well- 
developed eggs, whereas the worms taken in January are of 
various sizes and mostly with very small eggs or none at all. 
The small worms taken in January are the young of the 
preceding autumn which have not attained full size. If the 
worms had remained inactive until the ice melted, it is diffi- 
cult to understand how their increase in size and the growth 
of the eggs could have occurred in so short a time as three 
or four days. I believe, therefore, that they must have spent 
the month of February and the early part of March in the 
