STUDIES ON THE DEVELOPMENT OF TWO SPECIES OF STROMBIDAE FROM THE RED SEA

STUDIES ON THE DEVELOPMENT OF TWO SPECIES

OF STROMBIDAE FROM THE RED SEA

By
A. M. Eisawy, Ph. D.
Institute of Oceanography & Fisheries,

Academy of scientific Research & Technology, Cairo, A.R.E.

and
A. E. Sod I, M. Se.
Institute of Oceanography and Fisheries, Alexandria, A.R.E.
BULLETIN OF THE INSTI’£IT’I’E OF OC:EJANOGRAPHY & FISHEIUES 259
SUMl\ilARY
l.-Strombus giJJ?rulus lays smlll faint yellow solitary
eggs (90/-l) arranged in a very thin long thread, which
is also coiled; entangled and coated with fine sand
granules and is form~d in triangular mass of about 3
to 5 ems. across. The first two cleavages are equal.
D~ve1opment proceeds rapidly and the free swimming
veliger larva hatches out after 3 to 4 days of spawning
It possesses a transparent bilobed velum (37/-l x 52/-l),
a large triangular foot with its anterior constricted
region carrying a tuft of small cilia and two rose spots
on the sides of its metapodium, and a transparent larval shell of about one whorl (l05 x 100M).
2.-Strombus fasciatus deposited, in the laboratory,
its coiled and entangled ribbon which WaS glued as no
sand granules were provided. The yelloW eggs (l30M)
are arranged in rows of five eggs and a median one
between the row. The larvae could not be obtained as
all embryos died after three days of spawning.