208 
BULLETIN OF THE BUREAU OF FISHERIES 
foot, apparently through a rupture of the body wall. It is generally assumed that 
the contraction of the circular fibers of the foot and visceral mass forces this fluid 
to extend the foot by hj'draulic pressure. 
SPAWNING 
In most mollusks the sexes are separate; in a few, however, both eggs and 
sperm are produced by the same individual. In the razor clam, as in most forms, 
all observations have shown each individual to have germ cells of one kind only. 
The reproductive material is cast into the water at spawning time, and there fer- 
tilization and further development take place. 
Only by examination of the gonads is it possible to tell the sex of the clam. 
There are no superficial characters that betray the sex. If the contents of the 
gonads are spread on a glass slide or on a scalpel, a marked difference between sexes 
is apparent. The ova have a granular appearance, in contrast to the viscous homo- 
geneous mass in whicli the sperm is found. The sexes of the entirely immature 
clams can be determined only by microscopic examination of tissue, which was not 
carried out in this case while in the field. A large number of clams in more ad- 
vanced stages of maturity were examined and the sex recorded. This was done 
for two reasons — to deteimine the stage of maturity and to make sure that both 
sexes were equally represented- As far as has been determined both sexes pass 
tlirough similar stages in an equal period of time, and from the standpoint of 
maturity and growth they do not differ, hence, in the following calculations the 
sexes have been combined. 
TIME OF SPAWNING 
Data were obtained from the 1923 and 1924 spawning seasons on the Wash- 
ington coast (McMillin, 1923). These two spawnings differed somewhat and may 
represent two extremes. As described in the above reference, the 1923 spawning 
took place on May 30, 31, and June 1. It was practically simultaneous, and the 
major portion was completed in a very short time. As a result of tliis spawning 
a heavy set of J^oung was produced, the average per square foot on the whole beach 
numbering more than 1,400. The spawning of 1924 was different, apparently be- 
cause the temperature during May was variable and the average remained low. 
Spawning started on a rise of temperature on June 12, the rate of discharge of 
eggs was reduced by lowered temperature on June 14, and after that spawning 
continued slowly for two weeks. Although the action was slow, all observations 
showed the clams to be acting in unison, and at any one time all seemed to be in 
the same condition. The result of this year's spawning was negligible, no speci- 
mens representing this class having since been found. 
In 1923 the spawning on the Oregon coast was not followed. On the North 
Beach section of Washington, extending from Willapa Harbor to the Columbia 
River, spawning started on May 19. On the section beween Willapa and Grays 
Harbors it started on May 24, and on the Copalis section, as already described, 
on May 30. In each of these sectors the whole population of the beach spawned 
at the same time. No data were collected for the Queets and Kalalock beds of 
