. A manual of zoology. Zoology. III. SPOROZOA 185 by a pit at one point, tlie cytostome, near which is the nucleus surrounded by an aggregation of protoplasm which sends branching threads into the jelly of the body. At the entrance to the cytostome is a fiagellum, used in feeding but not in locomotion, and a band-like tentacle consisting of an outgrowth of the body membrane with a transversely banded muscular axis; it moves slowly with a swinging motion, Noctiluca reproduces by simple fission (progamic repro- duction) and by formation of swarm spores ( ? mctagamic reproduction) (fig. 144,. Fig
. A manual of zoology. Zoology. III. SPOROZOA 185 by a pit at one point, tlie cytostome, near which is the nucleus surrounded by an aggregation of protoplasm which sends branching threads into the jelly of the body. At the entrance to the cytostome is a fiagellum, used in feeding but not in locomotion, and a band-like tentacle consisting of an outgrowth of the body membrane with a transversely banded muscular axis; it moves slowly with a swinging motion, Noctiluca reproduces by simple fission (progamic repro- duction) and by formation of swarm spores ( ? mctagamic reproduction) (fig. 144,. Fig. 144.—Noctiluca millaris (in part aiter Cienkowski). A, entire animal;/, fiagellum; 11, nucleus; 0, cytostome, beside it the 'tooth' and 'Up'; <, tentacle; B, C, upper end \\ith two stages in the formation of zoospores; D, zoospores. B, C, D). In the latter two individuals lose tentacles, flagella, and cystos- tomes, and conjugate; after mutual nuclear fertilization ( ?) the animals separate, while the protoplasm in each collects in a disc which, by successive divisions, is converted into numerous uninucleate oval germs which at first project from the sphere, then separate and form small flagellate spores whose history is not known. Leptodiscus mcdusoides of Europe looks and swims like a small medusa. Craspedotdla/* Class III. Sporozoa. The Sporozoa are exclusively parasitic, and this has modified their feeding, movements and reproduction and in very similar ways. ]\Iany of them live as parasites in cells ('Cytosporida') as long as their size will permit; and after they have left the host cell, they live on fluid, not on solid food, hence they lack all arrangements for taking food, even in those cases where the body is covered with a cuticle. As a rule, there is also a lack of locomotor structures; but the occasional presence of amoeboid motion or flagella indicates a near relationship with rhizopods and flagellates, so that it is difficult to draw sharp lines between the
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1912
