36 U. S. BUREAU OF FISHERIES 
ing approximately one-sixth of the space between the liver and the 
body wall, while in the prespawning period virtually all of this space. 
is occupied by gonad tissue. The shrinkage of the gonad follicles 
continues through September, when the gonads, upon superficial ex- 
amination, appear to be in a wintering state. A more detailed study,, 
however, reveals that only by the end of October, when the water 
temperature is still about 15° C., is the shrinkage completed. Histo- 
logical studies show that the follicles are few in number and small 
in size and are scattered in the form of small islands through the con- 
nective tissue between the body wall and the digestive gland. Most 
of the follicles are confined to the portion of connective tissue lying 
immediately behind the body wall, but a few are found near the liver. 
The gonads remain in this state until spring. The sexes are dis- 
tinguishable throughout the winter for the female follicles, besides 
having indifferent cells, always possess a large number of small young 
odcytes. The male gonads containing gonia and a few spermatocytes 
are characteristically different in appearance from the female gonads. 
Although changes occur in oyster gonads during the winter, it 
cannot be stated that the gametogenetic activities of the oyster are 
entirely suspended until the following spring, because in March 
when the water temperatures of Long Island Sound are at or near 
the freezing point, a slight increase in the size of the follicles and 
in the number of cells can be noticed. During April and the early 
part of May the follicles in many cases shown some increase In size 
parallel with the increase in the number of sex cells. In the middle 
of May, when the water temperatures reach about 10° C., apparently 
ripe spermatozoa may be found in some males. From this date on, 
very rapid changes occur. Simultaneously with the marked increase 
in gametogenetic activities, the follicles begin to proliferate and ex- 
pand in all directions, but largely toward the liver. During the first 
week of June (water temperature 14°-15° C.) the expansion of the 
gonad follicles is so rapid that in a few days almost the entire space 
available for the gonad tissue is occupied, and the gonad follicles 
extend from the body wall to the boundaries of the digestive gland. 
The production of spermatozoa and ova enters its final stage and in 
a few weeks spawning follows. 
BIOLOGY OF THE HARD CLAM 
In an investigation of the life history of the hard clam, or quahog 
(Venus mercenaria), Dr. Loosanoff found that young clams possess 
distinctly bisexual gonads with a very strong predominance of males. 
A special study was therefore made of the sexual phases and devel- 
opment of the gonads of this mollusk. Observations showed that, 
hard clams spawn in the laboratory at temperatures ranging from 
23° to 30.2° C., the largest number of males spawning at 25°-26° C., 
while the females require a higher temperature of 29° C. 
OYSTER PESTS 
_ Biology and control of starfish—The work on starfish was con- 
tinued at the Milford Laboratory and in Long Island Sound by 
Dr. Loosanoff with the assistance of Dr. Robert Burrows. 
