Ultrastructural studies on accessory nuclei in developing oocytes of the crustacean, Siphonophanes grubei.

Numerous accessory nuclei (AN) occur within peripheral cytoplasm of Siphonophanes grubei oocytes. They exhibit typical nuclear structure, with double membrane envelope pierced by pore complexes. Although no explicit evidence was shown, indirect arguments exist indicating that AN originate from the oocyte nucleus. Presence of clumps of DNP material within AN suggests that AN might play some role in amplified DNA metabolism. Participation of AN in cellular membrane elaboration is also postulated.