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PACIFIC SCIENCE, Vol. XXI, April 1967 
tained at 30 and 35 ppt, 30°C, all died within 
the first two days following hatching and are 
not included in Figure 9. Mortality of most 
larval stages was higher at 25 °C than at 20 °C 
Mortality of any one zoeal stage at 20 °C does 
not exceed 16%, while at 25 °C mortality with- 
in one stage (Stage V) was as high as 36%. 
At 25 °C, there was a tendency for the mortality 
to be higher in the later larval stages than in 
the early zoeal stages. Survival to the crab 
ranged from 2 to 10% at 25 °C and from 38 
to 45% at 20°C. 
DISCUSSION 
Larval Stages 
A comparison of the larvae among species of 
the same subfamily as Cyclograpsus cinereus is 
limited to descriptions of Sesarma cinereum 
(Hyman, 1924; Costlow and Bookhout, I960), 
Sesarma reticulatum (Hyman, 1924; Costlow 
and Bookhout, 1962) and Sesarma picta 
(Aikawa, 1937). The number of zoeal stages 
varies considerably within those species of 
Sesarminae which have been described. C. 
cinereus has five zoeal stages, S. cinereum has 
four zoea (Costlow and Bookhout, I960) and 
S. reticulatum has three zoeal stages (Costlow 
and Bookhout, 1962). Aikawa (1937), while 
describing the first stage zoea of S. picta from 
the plankton, does not indicate the total num- 
ber of larval stages of this species. The first 
zoea of C. cinereus is quite distinctive in that 
the dorsal spine is gibbose. In all subsequent 
zoeal stages, when the dorsal spine is straight 
only C. cinereus has lateral spines. All the larval 
stages of C. cinereus may be further differen- 
tiated from zoeae of the three species of 
Sesarma by the absence of a knob on each 
lateral surface of the third abdominal segment 
of larvae of C. cinereus. 
Among the Chilean species of the family 
Grapsidae the larvae of only one, Grapsus 
grapsus L., have been described to date 
(Aikawa, 1937). Only the first zoea was de- 
scribed and may be differentiated from the 
first zoeal stage of C. cinereus by the presence 
of the lateral knob on the third abdominal seg- 
ment of G. grapsus as well as by the gibbose 
dorsal spine of C. cinereus. 
The megalops of C. cinereus differs from the 
megalops of S. cinereum and S. reticulatum in 
several respects. The main differences can be 
observed in the rostrum, telson, antennule, and 
second maxilliped. The rostrum of C. cinereus 
megalops is not depressed as in S. cinereum 
(Costlow and Bookhout, I960), and does not 
have a rostral spine as in S. reticulatum (Cost- 
low and Bookhout, 1962). The telson of C. 
cinereus bears only 3 setae on the distal margin, 
while the telsons of S. cinereum and S. reticu- 
latum bear 8 setae and 6 setae, respectively, plus 
lateral spines. In C. cinereus the unsegmented 
flagellum of the antennule is present, while in 
S. cinereum and S. reticulattim the unsegmented 
flagellum is absent and replaced by a single seta. 
The epipodite of the second maxilliped is 
present in the megalops of C. cinereus but 
absent in S. cinereum and in S. reticulatum. 
Of all the other megalops of the family 
Grapsidae which have been described to date, 
none are found in Chilean waters. However, it 
should be noted that the megalops of C. 
cinereus bears a greater resemblance to mega- 
lops of Hemi grapsus nudus and H. ore gone sis, 
which belong to the subfamily Varuninae and 
were described from the Pacific coast of Canada 
by Hart (1935), than to megalops of the sub- 
family Sesarminae. 
A more detailed comparison of the mor- 
phology of larvae of C. cinereus with larvae of 
other closely related forms in Chilean waters 
must await additional descriptions. 
Larval Development 
The adults of C. cinereus are normally con- 
fined to the area from Ancon, Peru to Calbuco, 
Chile on the western coast of South America 
(Garth, 1957). One extra limital locality, 
Panama, has also been recorded (Rathbun, 
1910, 1918). The habitat of the adults is in 
the upper level of the intertidal region, where 
they live under stones in the coarse sand. 
Ovigerous females have been observed in the 
Montemar region throughout the year with the 
exception of February. The principal spawning 
period, however, appears to be from July 
through November, when more than 60% of 
the population is ovigerous. During this period 
the water temperature increases from 12°C to 
14°C. The salinity of the water in which larval 
development occurs is quite stable, ranging 
