Abstract
Formation of the egg-membrane and the attaching-filaments of the marine goby Pomatoschistus minutus was studied with electron microscopic autoradiography using the tracer L-[3H]-proline. The egg-membrane is formed in the chronological sequence as follows: first labeled material is found in the oocytoplasm by 15 min post-injection, in Golgi bodies by 30-60 min, in dense-cored vesicles and pinocytotic vesicles by 3h and the substance of the egg-membrane by 12-24h post-injection. This suggests that the material forming the egg-membrane is synthesized in the oocytoplasm, concentrated in the Golgi bodies and then transfered via densecored and pinocytotic vesicles to the developing egg-membrane. In the follicle epithelium first label appears in stage II and III oocytes at 30 min post-injection and reaches the maximum concentration in the endoplasmic reticulum by 24h. These findings suggest that the egg-membrane of Pomatoschistus minutus is produced by the oocyte itself, whereas the attaching-filaments are synthesized by the endoplasmic reticulum of the follicle cells. Therefore according to the classical definition of Waldeyer (1906) the egg-membrane of this species is a primary envelope, while the attaching-filaments represent a secondary envelope or chorion.
