Oogenesis in oniscus asellus

Abstract

Basophil oogonia from the ovary wall slip into the lumen, some degenerating, others forming the oocytes, which soon become oxyphil. Fatty and proteid yolk are formed, the former directly by swelling of the Golgi elements, which are perinuclear in young oocytes, but later evenly distributed. Proteid yolk forms directly from the mitochondria, which are at first diffuse, then collect in a perinuclear zone and commence yolk formation. The mitochondrial yolk then passes out to a peripheral zone. No nucleolar activity is described in the oocytes. In centrifuged oocytes 3 zones are distinguished, the upper containing fatty yolk and Golgi bodies; the middle, fatty yolk, Golgi bodies, mitochondria and the nucleus; and the lower zone containing a little fatty yolk, and most of the mitochondrial yolk. These results are compared with those of Gatenby and Nath, and of Harvey, on Lumbricus, of Ludford and Brambell on Patella, of King and Nath on Lithobius, and of Hirschler on ascidians.