22 
PACIFIC SCIENCE, Vol. XVIII, January 1964 
typically carried out by females of this species. 
Ovaries removed from ovigerous females in 
March most frequently showed no development, 
though a few had some eggs apparently left 
from the previous brood. Cleaver (1949:79-80) 
states that May and June are the peak months 
for copulation in C. magister and that the ma- 
jority of the females carry eggs between the 
first of November and the last of February. A 
check of this latter species by Cleaver on Febru- 
ary 19, 1947, showed that 86.5% of the females 
had or were carrying eggs. Thus, there is a 
similarity in the timing and the procedure of 
the reproductive cycle of C. magister and C. 
productus. Both show a considerable lapse of 
time between copulation and egg deposition. 
The eggs of C. productus are bright orange 
when first deposited. These gradually become 
more brownish in color and become hyaline and 
gray by hatching time. Egg masses were not 
counted for this species. 
COPULATION: Copulation of C. productus is 
similar to that described in this paper for C. 
oregonensis and by others (Churchill, 1918:105; 
MacKay, 1942:18; Cleaver, 1949:79-80; Knud- 
sen, 1960:7), in that a courtship period pre- 
cedes the molting of the female and copulation 
follows the process of molting. As discussed for 
Hemigrapsus oregonensis in this paper, there 
seems to be some attraction, such as the release 
of molting-hormones by the female, so that 
males may identify females that are about to 
molt. Unlike Cancer magister (Cleaver, 1949: 
80 ) , pairs of C. productus do not separate fol- 
lowing the act of copulation; rather, the male 
continues to protect the female for several days. 
A check of the female exuvium shows that the 
spermathecae are removed at the time of molt- 
ing, as recorded by Cleaver. Unlike C. oregon- 
ensis, this species does not go into seclusion 
during the time of courting, but moves freely 
about at this time. Courting pairs are frequently 
seen up on pilings where the male may feed, or 
running across the sandy substrate. In the aqua- 
rium captive males tend to be polygamous, as 
is suggested by Cleaver for C. magister. 
Cancer gracilis 
HABITAT: For a discussion of the habitat of 
C. gracilis see C. productus. This species was 
encountered only in sympatry with C. productus 
when the former species was present in the 
intertidal zone. However, the habitats in which 
both species occur are quite sandy, and approach 
the extreme in sandiness for C. productus. 
FEEDING HABITS: No analysis of stomach con- 
tent was made for C. gracilis. This species was 
seen feeding in the identical situation with C. 
productus. Crabs were common both on the 
pilings, feeding on barnacles, and at common 
mess with C. productus feeding on fish detritus. 
From general appearances it would seem that 
this crab uses approximately the same food as 
C. productus. 
REPRODUCTIVE ACTIVITY: Field records for 
C. gracilis, other than those of copulation and 
courtship, are almost totally wanting. Our lab- 
oratory records suggest that the reproductive 
cycle is about identical with that of C. produc- 
tus. Females in the laboratory produced egg 
masses between the months of December and 
April. Whether or not a second brood is pro- 
duced in nature is unknown, as only a few lab- 
oratory animals produced a second brood. How- 
ever, the known second broods produced in the 
laboratory consisted of very few eggs as com- 
pared with the normal brood. The time of court- 
ship and copulation coincides with that of C. 
productus . 
COPULATION: During the summer months 
numerous pairs of C. gracilis were seen feeding 
under the pilings at Point Defiance. However, 
during the reproductive periods of the year pairs 
or individuals became less abundant and soon 
became absent from the intertidal fauna of those 
areas observed. From a few pairs isolated in the 
Point Defiance aquarium and from some field 
observations we have noted that the process of 
copulation and courtship is identical with that 
of C. productus. Courting pairs of C. gracilis 
were found amongst other noncourting indi- 
viduals and would move about the substrate very 
freely. The larger size of this species may ac- 
count for the fact that it needs little protection, 
as does C. oregonensis. Males were discovered 
carrying both hard-shelled and soft-shelled fe- 
males. When the female of the pair was soft- 
shelled, most frequently the pair was in the act 
of copulation. Unlike C. magister , the males of 
this species protect the females after copulation. 
