. Algæ. Vol. I. Myxophyceæ, Peridinieæ, Bacillarieæ, Chlorophyceæ, together with a brief summary of the occurrence and distribution of freshwat4er Algæ . t improbable, however, that this articu-lation is only apparent, as in Aphanoch&te, and that the bristles are nottruly septate. Lambert found that the bristles attained a length of4*5 mm. The most curious species of the genus is C. Nitellarum Jost (95;Lewis, 07), which is endophytic in the outer layers of the wall of speciesof Nitella. In consequence of its habit the cells are greatly flattened withthin cell-walls; they are also of a much mor
. Algæ. Vol. I. Myxophyceæ, Peridinieæ, Bacillarieæ, Chlorophyceæ, together with a brief summary of the occurrence and distribution of freshwat4er Algæ . t improbable, however, that this articu-lation is only apparent, as in Aphanoch&te, and that the bristles are nottruly septate. Lambert found that the bristles attained a length of4*5 mm. The most curious species of the genus is C. Nitellarum Jost (95;Lewis, 07), which is endophytic in the outer layers of the wall of speciesof Nitella. In consequence of its habit the cells are greatly flattened withthin cell-walls; they are also of a much more irregular shape than those ofany other species of the genus. 316 Ulotrichales Each cell possesses one nucleus, and a single parietal chloroplast withone or, more rarely, two pyrenoids. Asexual reproduction takes place by means of large ovoid zoogonidia,which are biciliated, without stigma, and with a large parietal arise singly from the cells of the thallus, more especially from theterminal cells of the branches, and they generally escape from the mother-cell by a circular orifice. On corning to rest the zoogonidia germinate. I1 Fig. 208. Coleochsete pulvinata A. Br. 1, young zoogonidangium (?) ; 2 and 3, young antberidia(a) and oogonium (o); 4, oogonium (o) just before the opening of tbe trichogyne and emptyantberidium (a) ; 5, oogonium (o) after opening; 6, zygote still with distinct male (sk) andfemale (ek) nuclei; 7, zygote which has become surrounded by tbe spermocarp; 6, thedivisions of the hypnozygote (or oospore after a period of rest). In the vegetative cells infig. 7: A, nucleus ; chr, chloroplast; py, pyrenoid. (After Oltmanns.) directly into new plants; those of C. Nitellarum penetrate between thelamellae of the wall of Nitella. The first division of the quiescent zoogonidiumresults in a dorsal and a ventral cell and the disc is developed from theventral cell. The sexual reproduction is of a high type. The sexual organs areoogonia and anther
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