extentling froni the foregrit to the posterior end of the carapace.
However, they extend into t,hc abdominal segment in some other
species of ASergia, In Acrtcs spp. the elongated ovaries reach to the
sixth ebdominul wgrnent. Tlw ovaries am visible through the thin
carapace in the wmitranq)tcrri i t sprcies ; they turn from light yellow
in the early stages of maturity to opaque bluish-grey with increasing
development in Sergin luc~ns, whereas they become yellowish-green
wlicn mature in Acetcs japonicw. I n the Penaeidea it can be determined whether copulation has taken place from the structural change
in the thelycun~ (Rpermatophore receptacle), as Yoshida (1949)
observed in Acetee. Generally, copulution takes place a few days before
epowning. Tho morphology of the reproductive system is described
in detriil for LSargPstes similie and Acftcs americunus carolinue Hansen
(us A. carolinria) by Genthe (1969) and Burkenroad (1934) respectively.
Exclept for Lucifer, which has clusters of eggs attached by short
stalks to the third pereiopod until hatching (Brooks, 1882), all Penaeidea
shed their eggs into the water. The spawning of Sergia lucens takes
place in the shallow layers at night when females with ripe ovaries
rise toward the surface. The egg laying is an intermittent process
which lasts up to, 25 minutes. The eggs are spherical, light greenishbluish-greg, and about 0.25 mm in diameter. The perivitelline space
is hardly seen in the egg throughout development. The eggs are mostly
drifting in depths ranging from 10 to 50 m where they were
spawned, because they have a density similar to that of seawater.
Measurement,s in the 1iLborutory suggest that the eggs float upward
u t about 22 cm per hour in wiiter of 32"/,, salinity a t a temperature
of 22°C. The buoyancy rate, of cour~e, decreases in waters of the
same salinity but of lower temperuturc*s. As the time elapsing between
sptswning ot'the egg and hatching of the nsuplius is 24-36 hours under
normal cunditioiis, the ctbovcb buoyancy rate would cause eggs at 30 m
dept,h to float to 22-25 m ict, the time of hatching. Eggs of Acetes
japonicw me green and planktonic (Soejima, 1926). They gradually
increase t h e perivihlline spwe and in the later stages of development
they swell 2.0-2.6 times in diarnetcr.
The egg8 of Caridea are incubated by the female and are attached
to spccialized setae on the abdominal appendages (see Yonge, 1955).
The eggs are generally elliptical and large, but the number of eggs is
few compared with that in Yenaeidea of similar size (Table IV).
As pointed out by Gurney and Lebour (1941)) the genera of the
Oplophoridea fall into two groups according to the size of eggs. Eggs
of O p l o p b ~ ,
Ephyrinn, Hgmenodora and Systellaapis are much larger
than those of Acunthephyra, Meningodora and Notostomw. The
However, they extend into t,hc abdominal segment in some other
species of ASergia, In Acrtcs spp. the elongated ovaries reach to the
sixth ebdominul wgrnent. Tlw ovaries am visible through the thin
carapace in the wmitranq)tcrri i t sprcies ; they turn from light yellow
in the early stages of maturity to opaque bluish-grey with increasing
development in Sergin luc~ns, whereas they become yellowish-green
wlicn mature in Acetcs japonicw. I n the Penaeidea it can be determined whether copulation has taken place from the structural change
in the thelycun~ (Rpermatophore receptacle), as Yoshida (1949)
observed in Acetee. Generally, copulution takes place a few days before
epowning. Tho morphology of the reproductive system is described
in detriil for LSargPstes similie and Acftcs americunus carolinue Hansen
(us A. carolinria) by Genthe (1969) and Burkenroad (1934) respectively.
Exclept for Lucifer, which has clusters of eggs attached by short
stalks to the third pereiopod until hatching (Brooks, 1882), all Penaeidea
shed their eggs into the water. The spawning of Sergia lucens takes
place in the shallow layers at night when females with ripe ovaries
rise toward the surface. The egg laying is an intermittent process
which lasts up to, 25 minutes. The eggs are spherical, light greenishbluish-greg, and about 0.25 mm in diameter. The perivitelline space
is hardly seen in the egg throughout development. The eggs are mostly
drifting in depths ranging from 10 to 50 m where they were
spawned, because they have a density similar to that of seawater.
Measurement,s in the 1iLborutory suggest that the eggs float upward
u t about 22 cm per hour in wiiter of 32"/,, salinity a t a temperature
of 22°C. The buoyancy rate, of cour~e, decreases in waters of the
same salinity but of lower temperuturc*s. As the time elapsing between
sptswning ot'the egg and hatching of the nsuplius is 24-36 hours under
normal cunditioiis, the ctbovcb buoyancy rate would cause eggs at 30 m
dept,h to float to 22-25 m ict, the time of hatching. Eggs of Acetes
japonicw me green and planktonic (Soejima, 1926). They gradually
increase t h e perivihlline spwe and in the later stages of development
they swell 2.0-2.6 times in diarnetcr.
The egg8 of Caridea are incubated by the female and are attached
to spccialized setae on the abdominal appendages (see Yonge, 1955).
The eggs are generally elliptical and large, but the number of eggs is
few compared with that in Yenaeidea of similar size (Table IV).
As pointed out by Gurney and Lebour (1941)) the genera of the
Oplophoridea fall into two groups according to the size of eggs. Eggs
of O p l o p b ~ ,
Ephyrinn, Hgmenodora and Systellaapis are much larger
than those of Acunthephyra, Meningodora and Notostomw. The