. Biological lectures delivered at the Marine Biological Laboratory of Wood's Holl [sic]. Biology. 222 BIOLOGICAL LECTURES. It is a temporary stage like this in Tctramitus or Paramceba that lends support to Schaudinn's alternative. Intermediate stages between this condition and the permanent intranuclear sphere may be seen in numerous flagellates, such as CJiilotiionas and some species of Ti-achelomonas, where no nuclear mem- brane surrounds the chromatin granules. On the other hand, it cannot be denied that there is very strong evidence for Hert- wig's view in the observations of Schaudinn up
. Biological lectures delivered at the Marine Biological Laboratory of Wood's Holl [sic]. Biology. 222 BIOLOGICAL LECTURES. It is a temporary stage like this in Tctramitus or Paramceba that lends support to Schaudinn's alternative. Intermediate stages between this condition and the permanent intranuclear sphere may be seen in numerous flagellates, such as CJiilotiionas and some species of Ti-achelomonas, where no nuclear mem- brane surrounds the chromatin granules. On the other hand, it cannot be denied that there is very strong evidence for Hert- wig's view in the observations of Schaudinn upon the nuclei of Foraminifera,! and of Siedlecki upon Coccidiida.^ In both cases the nuclei first appear as solid masses of chromatin, with (Coccidiida) or without a nuclear membrane. These become vacuolated in Foraminifera, and membrane and nuclear reticu-. FiG. 4.— Formation of nuclear membrane and reticulum from the chromatin of an originally homogeneous chromatosphere in Calciizcba (after Schaudinn). lum, as well as the definitive chromatin, are all derived from the homogeneous chromatosphere (Fig. 4). There is no mitotic figure, however, the chromatin fragmenting by what Schaudinn calls "multiple nuclear division," and the sphere, as such, does not appear in either case. Even in the lowest forms the sphere apparently exerts some force of attraction, perhaps chemotactic, upon the chromatin, and this force may or may not be strong enough to keep the granules permanently aggregated ; if not, the distributed nucleus results ; if so, the intranuclear condition of the sphere is the outcome. In Paramceba, Noctiluca, in diatoms, and in the majority of the Metazoa and plants, a nuclear membrane is formed, and the sphere remains outside of the nucleus. As a 1 Biol. Centralbl., 1894, Bd. xiv. - Aim. d. riust. Pasteur, tome xii, Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and
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