. A textbook of invertebrate morphology [microform]. Invertebrates; Morphology (Animals); Invertébrés; Morphologie (Animaux). 82 INVERTEBRATE MORPUOLOGT. Noctiluca is of considerable physiological interest, since it is one of the forms to wliich the phosphorescence of the ocean is due. The cause of the liglit and its character are, however, as yet unknown. Reproduction in the Flagellata.—The most frequent method of reproduction in all the orders of the Flagellates is simple division, either transverse or longitudinal. Encystment, fol- lowed or not as the case may be by spore-formation, is also
. A textbook of invertebrate morphology [microform]. Invertebrates; Morphology (Animals); Invertébrés; Morphologie (Animaux). 82 INVERTEBRATE MORPUOLOGT. Noctiluca is of considerable physiological interest, since it is one of the forms to wliich the phosphorescence of the ocean is due. The cause of the liglit and its character are, however, as yet unknown. Reproduction in the Flagellata.—The most frequent method of reproduction in all the orders of the Flagellates is simple division, either transverse or longitudinal. Encystment, fol- lowed or not as the case may be by spore-formation, is also common, and when accompanied by spore-formation may be preceded by the conjugation and fusion of two individuals. In Cercomonas the spores are exceedingly abundant and small, presenting the appearance of minute granules even under the highest powers of the microscope, but in other forms, as Chlamydomonas, the spores are larger and much fewer in num- ber, being only 4 or 8 in this particular case. An interesting modification occurs in closely-related species (Fig. 16), some individuals of which divide into a number of small spores {microspores), while others undergo a more restricted division and give rise to a few large spores [niacrospores). The latter develop directly into the adult forms, but the microspores show a tendency to conjugate in pairs before undergoing further development. This differentiation of two kinds of spores is carried still farther in other forms where neither. Fia. 16.—1. Phacotus lenticttlaria; 3, Macuosi'ouks and Mickosi'okes op TIIK HAMIfi Sl-EOIES (after Ui^). «cA = shell. n = nucleus. macro- nor microsi)orea develop directly but further develop, ment is contingent upon the conjugation of a micro- with a mucroHpoio. In this ] certain celh spliere, enla when they 1 cells Avhich (laughter co' to this a se vidu.'ils grad surface of tL to enlarge, : frecpiently, f tliigella; tlies ova develop tion with spt colony do nc tegrate and < it
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