Brachyura and Anomura of Puget Sound — Knudsen 
21 
together in approximately equal numbers. With the 
onset of sexual maturity, a definite segregation occurs. 
Adult females are comparatively rare in Grays and 
Willapa Harbors, although in some areas of the ocean 
they are overwhelmingly abundant, particularly in the 
late winter and early spring months. 
Cleaver further notes (1949:67) that some 
data suggest an offshore migration for this 
species and confirm a coastwise migration. It is 
quite possible that C. productus may be similar 
to C. magister in having an offshore or vertical 
pattern in migration. Prasad and Tampi (1951: 
676) show that other members of the family 
Cancridae, in particular Neptunus pelagicus, 
segregate according to size and sex in a manner 
similar to that described above. 
It was interesting to note that this species 
displays a negative rheotaxis in response to the 
lowering of the tide. It was frequently observed 
that this species continuously moved ahead of 
the receding tide, without being "pushed” by 
the edge of the water or the reduction of the 
water level. In experimentation, crabs were re- 
leased into a 3 X 8 ft aquarium and allowed 
to become tank-adapted. It was noted that they 
moved about at random in the aquarium. At 
this time a stream of salt water was introduced 
at one end of the aquarium, so that a current 
was created along the bottom of the tank. The 
crabs oriented themselves and began moving in 
the direction of the current. The rate of crab 
movement roughly corresponded to the rate of 
current created in the tank. It is suggested that 
this species responds to weak currents created 
as the water recedes in the intertidal zone, and 
may govern its tidal migration mainly by these 
currents. 
FOOD AND FEEDING HABITS: C. productus is 
not secretive in its feeding but, rather, is often 
bold in its attempt to obtain food. It was regu- 
larly observed feeding on barnacles attached to 
pilings, or on dead fishes or other animal matter 
available in the habitat. Discounting the food 
supplied by fishermen in the form of cast-away 
fishes, barnacles seem to be the most consistent 
source of food. C. productus will feed around 
the base of pilings, or will climb up on the 
pilings in order to obtain this food. The large 
chela is used in breaking barnacles, while the 
smaller chela serves to transfer the barnacle to 
the mouth parts. Crabs of this species main- 
tained at the Point Defiance aquarium frequently 
captured and ate smaller crabs of the same spe- 
cies or other species. At such times C. productus 
merely waited motionless until the smaller crabs 
approached within striking distance, then lunged 
forward to capture the smaller crab, crushing 
the carapace with the large chela. In feeding 
experiments where crabs were secretly fed small 
pieces of fish with no light available for their 
vision (they were observed under red light), 
C. productus was able to locate pieces of food 
in a brief time. If water was circulated through 
the tanks at the time of feeding, so as to dis- 
tribute the meat juices more readily, the time 
required for locating food was greatly decreased. 
Probably this species uses tactile receptors, 
chemoreceptors, and eyes, either individually or 
in combination, in its feeding. 
REPRODUCTIVE ACTIVITY: Because of the se- 
cretive nature and/or disappearance of females 
during part of the reproductive season, field data 
are almost wanting concerning some phases of 
reproduction in C. productus. Many animals 
were maintained in the laboratory in order to 
augment our field observations. Copulating pairs 
could be found at almost any time of the year 
though they were numerous only in the summer 
and fall months. Beginning in June and con- 
tinuing on through July and August mating 
pairs are encountered regularly and in large 
numbers. Only one or two pairs were observed 
as late as the first of November. This species, 
like the other cancroid crabs, copulated just 
after the molting of the female. Egg deposition 
begins for a few individuals as early as October, 
and individuals may be found carrying eggs on 
the pleopods as late as the early weeks in June. 
Our records would tend to indicate that most 
of the females extrude eggs by December or 
January, and that most eggs hatch by late March 
or early April. In the laboratory three females 
which extruded eggs prior to December 20 had 
completed the hatching process by March 6. 
Two of these females then extruded new, but 
small, clutches of eggs without first molting or 
copulating. However, it was impossible to main- 
tain these females until the time of hatching, 
though the eggs appeared viable and in the 
process of development. Thus, it is not known 
if the female has sufficient stored sperm to 
fertilize a second brood, nor whether this is 
