ULTRASTRUCTURE OF DEVELOPING AMPHIBIAN EGG 157
FIG. 18. A diagrammatic presentation of the formation of the annulate lamellae
in Necturus. The sequence of events appears to involve: A, blebbing of the outer
membrane of the nuclear envelope; B, simultaneous release of the blebs takes
place; C, the row of blebs moves toward the periphery; D, several rows of released blebs; E, fusion of some of the vesicles takes place; and F, continued fusion
results in formation of the cisternae.
4. Vesicles
The most prominent organelles found in the cytoplasm of immature
oocytes, aside from mitochondria, are the vesicles. These are spherical,
optically empty structures, the largest having a diameter of 150 to 200 πΐμ.
In young Triturus oocytes, isolated vesicles are found distributed throughout the cytoplasm (see Fig. 12). As the oocyte matures, they are found in
increasing numbers and in some areas almost fill the cytoplasm. In yolkfilled oocytes they are found dispersed between the platelets.
5. Other Cytoplasmic Organelles
In addition to the organelles discussed in the previous sections, Wartenberg (1962) has reported the presence of other structural entities in the
cytoplasm.
FIG. 18. A diagrammatic presentation of the formation of the annulate lamellae
in Necturus. The sequence of events appears to involve: A, blebbing of the outer
membrane of the nuclear envelope; B, simultaneous release of the blebs takes
place; C, the row of blebs moves toward the periphery; D, several rows of released blebs; E, fusion of some of the vesicles takes place; and F, continued fusion
results in formation of the cisternae.
4. Vesicles
The most prominent organelles found in the cytoplasm of immature
oocytes, aside from mitochondria, are the vesicles. These are spherical,
optically empty structures, the largest having a diameter of 150 to 200 πΐμ.
In young Triturus oocytes, isolated vesicles are found distributed throughout the cytoplasm (see Fig. 12). As the oocyte matures, they are found in
increasing numbers and in some areas almost fill the cytoplasm. In yolkfilled oocytes they are found dispersed between the platelets.
5. Other Cytoplasmic Organelles
In addition to the organelles discussed in the previous sections, Wartenberg (1962) has reported the presence of other structural entities in the
cytoplasm.