6 
PACIFIC SCIENCE, VoL XVIII, January 1964 
30-gal aquaria of a plywood construction, one 
150-gal tank, and numerous smaller aquaria. All 
of these were supplied with running sea water 
and furnished with both barnacle-encrusted rocks 
and marine algae as required by the different 
species of crabs. A time switch controlled the 
lighting so that the length of "daylight” could 
be regulated. Different species of crabs were 
seldom mixed within the various tanks, to avoid 
competition and fighting. The cleaning of the 
tanks and feeding of the crabs twice weekly de- 
manded the full-time attention of one student 
throughout the entire project. 
REPRODUCTIVE CYCLE: Almost all of the data 
collected concerning the annual reproductive 
cycle of the various species studied were ob- 
tained by field collecting, and only where an 
indication is made to the contrary are the data 
obtained by laboratory observation. By selecting 
and preserving samples of the crabs collected, 
the development of ova within the ovaries could 
be watched and measured. Ovaries were studied 
by dissecting these and placing them on a tem- 
porary wet-mount microscope slide. They were 
then placed on a micro -slide projector and the 
projected ovary with its developing ova was 
measured by a predetermined metric scale. Size 
and color data were recorded in each case. 
Observations of crab copulation were made 
by chance. With the numerous field trips and 
continuous laboratory observation, many fine 
records were obtained. The crabs were at no 
time conditioned by hormones or isolated for 
copulation studies, and all records are considered 
to be normal and valid. 
The time of egg deposition was obtained 
from the field record. As many females as pos- 
sible or practical were collected bimonthly, and 
counts of the total number of females with eggs 
and studies of the egg condition were made. 
Incubation period is determined mainly from 
the total field record as plotted, or, from the 
literature. In few cases are the data obtained in 
the laboratory. In most instances it was felt that 
laboratory results may be altered somewhat due 
to some abnormal condition and therefore field 
records were used whenever possible. In some 
cases the actual mechanics of hatching were 
observed for various species of crabs. The num- 
ber of broods per year was determined by field 
observations, laboratory observations, and by 
the dissection of females carrying developing 
eggs on the pleopods. These dissections de- 
termined the nature and degree of development 
within the ovaries. All three means were used 
whenever possible to give an accurate picture 
of the number of broods per year. Some attempts 
were made to study the larval development by 
actually rearing larvae in the laboratory. By 
far the largest proportion of crabs in Puget 
Sound have already been studied and the de- 
scription of the larvae of these crabs is now 
being prepared for publication. Those species 
yet unstudied remain so because of difficulty in 
rearing them in the laboratory. Many species 
already known were run through the life cycles 
in part at least to compare both the morphology 
and ecology with the literature. 
FAMILY Grapsidae 
Hemigrapsus HABITAT: The two species of 
Hemigrapsus, nudus and oregonensis, will be 
treated together for the sake of comparison. The 
habitat of H. nudus is listed by Way (1917: 
358), as being a situation where rocks and 
stones cover a sandy substrate. MacKay (1931: 
189; 1943:151), Rathbun (1918:268), and 
others simply list the habitat as being among 
rocks nearshore. Schmitt (1921:274) describes 
H. nudus as being strictly a littoral species. 
Hiatt (1948:141) encountered H. nudus and 
H. oregonensis in what he calls "the second and 
less common biotope” of Pachygrapsus crassipes. 
This biotope is found most commonly in es- 
tuaries and bays, and consists of a gradation of 
very large boulders giving way to rock and stone 
and finally gravelly rubble as one proceeds from 
the offshore area towards the higher reaches 
of the intertidal zone. Hiatt mentions that 
Pachygrapsus crassipes is quite abundant around 
the larger boulders but is replaced by H. nudus 
and finally by H. oregonensis as one moves 
progressively toward the fine sandy or muddy 
substrate. 
Hemigrapsus oregonensis is thought of as 
living on muddy portions of the coast line 
(Way, 1917:359; MacKay, 1943:152; and 
others). Hiatt (1948:142) lists this species as 
being common in the third biotope of P. cras- 
sipes, along muddy shores of bays and estuaries. 
He describes the hiding places of this species as 
