6
CHR. P. RAVEN
//
/
FIG. 2. Ooplasmic segregation in Aplysia limacina. Distribution of vitamin C (presumably bound to Golgi bodies) during early cleavage. A. Random distribution in
immature egg. B. Annular concentration in mature egg. G. First cleavage. D. Four-cell
stage. E. Eight-cell stage. F. Ten-cell stage. G-H. Twelve-cell stage. /. Somewhat later
stage. After Ries, 1937.
In Physa (Mancuso, 1953) and Succinea (Jura, 1960) glycogen is at
first more or less evenly distributed, but shifts during maturation to the
vegetal part of the egg. At cleavage most of it passes into the macromeres ; later it is found in the inner germ layer. In Limnaea, the cells 4a,
4b and 4c (but not 4d) are rich in glycogen. Their descendants form a
horseshoe-shaped area surrounding the anterior border of the blastopore
(Raven, 1946).
Collier (1960a) found in the polar lobe of Ilyanassa a concentration of
CHR. P. RAVEN
//
/
FIG. 2. Ooplasmic segregation in Aplysia limacina. Distribution of vitamin C (presumably bound to Golgi bodies) during early cleavage. A. Random distribution in
immature egg. B. Annular concentration in mature egg. G. First cleavage. D. Four-cell
stage. E. Eight-cell stage. F. Ten-cell stage. G-H. Twelve-cell stage. /. Somewhat later
stage. After Ries, 1937.
In Physa (Mancuso, 1953) and Succinea (Jura, 1960) glycogen is at
first more or less evenly distributed, but shifts during maturation to the
vegetal part of the egg. At cleavage most of it passes into the macromeres ; later it is found in the inner germ layer. In Limnaea, the cells 4a,
4b and 4c (but not 4d) are rich in glycogen. Their descendants form a
horseshoe-shaped area surrounding the anterior border of the blastopore
(Raven, 1946).
Collier (1960a) found in the polar lobe of Ilyanassa a concentration of