EGG CAPSULES AND DEVELOPMENT OF THAIS SAVIGNYI DESHAYES

BULL. INST. OCERN. & FISH., A.R.E. VOL. 4, 1974
EGG CAPSULES AND DEVELOPMENT OF THAIS
SAVIGNYI DESHAYES
By
A. M. EISAWY

Tnstitute of Oceanography &; Fisheries Academy of Scientific

Research &; Technology, Cairo, A..R.E.
land
A. E. SoRIAL
lnstit,ute of Oceanography &; Fisheries Alexandria, A.R.E.

INTRODUCTION AND HISTORICAL

Thais savignyi is a predator shell driller gastropod on other economIC
species; and thus the study of its life history is important. Also, the identification of Prosobranch’s larvae that form a part of the temporary plankton of the Red Sea can help in studying the feeding habits of the ecouomic
p~lagic fishes.
Species of family Thaididae (or Purpuridae) were previously included
under family Muricidae of which only the development of three species from
the Red Sea (namely Murex (Phyllonatus) incarnatus Roding, Murex ramosus Linne and ]opas francolinum Bruguiere) were described (Gohar and
Eisawy, 1967). In the present work the biology and life-history of the oyster
driller Thais (=Purpura) savignyi Deshayes are througly studied.
From scattered literatures one can mention the important works as
fullowing : a spawn firstly described by Ellis (1756) under the name of
Cyathus marinus was found to belong to Purpura (Nucella) la;pillus Ueffreys,
1867 ; Lamy, 1929 ; Lebour, 1937 and others). Carpenters (1855) was the
fIrst who studied the embryology of P. lapillus. Other studies on the spawn
and development of this species were made by Koren & Danielssen (1857),
Selenka (1872), Mac Murrich (1887) and Pelseneer (1905 & 1911). Portmann (1925 & 1930) studying the egg capsules and development of this
species, suggested that the presence of nurse eggs were the result of fp.rtilization with apryene spermatozoa. In the same species, Risbec (1937) summarized the typical aspects of development, Lebour (1937) described the
capsules; Ankel (1937) studied the structure of the capsules, giving an account on the hatching process; and Thorson (1946) described the egg capsule and the hatching larva.
Esper (1830) described the spawn which was attributed by lolim to a
Natica species, but Lamy (1928) stated that it was similar to that of P.
chocolatum which had been described by d’Orbigny (1846) from Bolivia and
Peru.
d’Orbigny (lac. cit.) also described the spawn of P. (Stramontia) haemastoma = Thais haemastoma from Rio Janeriro. The egg capsules of the
same species which are yellowish to rose-coloured were studied from the
Gulf of Mexico by Burkenroad (1931), its development was studied by St.
Amant (1938 & 1957), the formation of the capsules by Franc (1941), its
breeding habitat, egg-capsules, developmental rate and larva by Butler (1954).