24 
PACIFIC SCIENCE, Vol. XVIII, January 1964 
bor region in eel grass ( Zoster a marina ), while 
Hart (1930:106) records it from kelp ribbons 
at Parry Bay. In the southern Puget Sound re- 
gion the majority of our specimens are found 
attached to those pilings which were very heav- 
ily encrusted with barnacles and other fouling 
organisms, or clinging to similarly encrusted 
rocks under the Narrows Bridge. Less frequently 
were specimens taken from Zostera beds. Those 
individuals taken from Zostera were frequently 
smaller, immature animals. The requisites for 
the habitat of this animal seem to be an area 
where there is, first, abundant food, and second, 
some situation where the crab may get up off 
the bottom and thus be exposed to continuous 
currents. Probably the currents are necessary for 
the crab’s survival. It is interesting to note that 
Garth (1958:199) lists the specimens from the 
Hopkins Marine Station at Monterey Bay, Cali- 
fornia, as not being from the intertidal zone. 
The fact that this species occurs below the 
intertidal zone in the south, where temperatures 
closely approximate those temperatures of the 
northern intertidal zone, would indicate that 
temperature may be a southern limiting factor. 
For at levels below the intertidal zone in the 
south this species could find a suitable habitat 
and source of food and still enjoy a much colder 
range of temperatures. Like Pugettia producta 
this species also has the dactylae somewhat mod- 
ified for holding on to kelp. This species may 
be more abundant in kelp than our records in- 
dicate, as our collecting in kelp was very limited. 
REPRODUCTIVE ACTIVITY: P. gracilis was 
often encountered at the Tacoma Narrows and 
was occasionally found at Point Defiance, but 
seldom were more than just a few of these ani- 
mals seen at any time. Thus, the total number 
of records for this species is too small to be of 
great significance. Garth (1958:199) cites col- 
lecting ovigerous females at Coos Bay, Oregon, 
when 14 of 16 specimens were with ova in late 
June, and in mid- July at Bodega Bay, California, 
in March and at Stewarts Point in November. 
In Puget Sound we have collected ovigerous 
females almost every other month throughout 
the entire year. During 4 of the 6 months in 
which no ovigerous females were encountered, 
only immature specimens were collected, and 
during 2 months, July and October, mature 
but nonovigerous specimens were observed. 
Specimens with very new dark purple eggs, 
intermediate reddish-brown eggs, or grayish- 
brown prehatch eggs could be found during 
almost any month of the year. Hatching was 
most frequently observed in May and June both 
in the laboratory and in the field. On the other 
hand, five out of eight specimens collected dur- 
ing the first week of August had very new dark 
purple eggs. It is not known whether one or two 
broods of eggs are produced annually. 
PRODUCTIVITY: The eggs within the egg 
masses of five specimens were counted. The hep- 
atic carapace width of these specimens ranged 
from 20 mm to 25 mm, and the number of eggs 
per brood range from 6,200 to 13,300, with the j 
average being 10,500 per brood. 
COPULATION: Accounts of copulation in the 
family Majidae seem to be absent in the litera- 
ture. The secretive nature of the spider crabs 
would probably cause such a vital process to go 
unobserved in the field or laboratory. Probably 
copulation occurs while the crabs are on pilings 
and thus the chance for observation may be 
poor. Detailed observation of P. gracilis in 
copulation was possible on only three occasions. 
The remarkable fact seems to be position as- 
sumed by the male and female, in that the male 
is oriented under the female with his ventral 
side upward. The only record of such a position 
is that of Hiatt ( 1948: 199) for a grapsoid crab, 
Pachygrapsus crassipes, and accounts given in 
this paper for the two species of Hemigrapsus. 
It is quite possible that the Majidae may re- 
semble the Grapsidae in respect to posture, and 
that the female-over-male position is more com- 
mon in the Brachyura than the literature would 
suggest. The many descriptions for the cancroid 
crabs (Williamson, 1903:101; Hay, 1905:405; 
Churchill, 1918:105; and others), have fostered 
the general opinions that ( 1 ) crabs copulate in 
a male-over-female position, and (2) many spe- 
cies copulate in a soft-shell condition. With the 
more recent literature on crab natural history 
the general pattern of brachyuran copulation is 
becoming more well known. 
P. gracilis was observed in copulo both in 
the Point Defiance laboratory and in the field. 
All of our observations were made in December 
and February, but the period of mating is prob- 
ably not limited to those months for reasons 
discussed below. In the laboratory pairs were 
