On the origin of the protein yolk in the oocytes of Aplysia depilans (Gastropoda, Opistobranchia).

In the oocytes of Aplysia depilans it has been observed electronmicroscopically that "gemmae" or "daughter-nucleoli" separate from the nucleolus. These "gemmae" after having overcome the nuclear membrane, would aggregate together, even after transformation, into yolk globules. These observations seem to give plausibility to the hypothesis that there is a close relationship between production of ribonucleoproteic material by the nucleolus and yolk production.