Note 148 — Chapter III
Reading edition
A protoplasmic network resembling in its essential features the one just described has been noticed by many observers in other ova. Fol has figured and described a network or sponge-like arrangement of the protoplasm in the eggs of Geryonia. (Jenaische Zeitschrift, Vol. VII.) Metschnikoff (Zeitschrift f. Wiss. Zoologie, 1874) has demonstrated its presence in the ova of many Siphonophoriæ and Medusæ. Flemming (Entwicklungsgeschichte der Najaden, Sitz. der k. Akad. Wien, 1875) has found it in the ovarian ova of fresh-water mussels (Anodonta and Unio), but regards it as due to the action of reagents, since he fails to find it in the fresh condition. Amongst vertebrates it has been carefully described by Eimer (Archiv für Mikr. Anat., Vol. VIII.) in the ovarian ova of Reptiles. Eimer moreover finds that it is continuous with prolongations from cells of the epithelium of the follicle in which the ovum is contained. According to him remnants of this network are to be met with in the ripe ovum, but are no longer present in the ovum when taken from the oviduct.