Main Content

The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 975

Kaneda Masao; Phase contrast microscopy of cytoplasmic organelles in the gymnostome ciliate Chlamydodon pedarius. J.Protozool. 7(4):306-313, 1960

Reprint

In File

Notes

Chlamydodon pedarius has peculiar and interesting cytoplasmic organelles, such as the pharyngeal basket and the cross-striped band, and exhibits plasmotomy of an uncommon type at the division stage. For comparison on the results of observations on fixed and stained material and on living material examined with phase contrast, and because of finding important differences in such a comparison, this morphological study of the cytoplasmic organelles was undertaken. The cilia, arranged in about forty rows only on the ventral surface, the anterior part of which shifts out of the dorsal body, bending to the dorsal side, are almost the same everywhere, about 5 u in length. The cross-striped band, encircling the body surface so as to divide it into dorsal and ventral parts, has the power of movement, such as folding of the semicircular trichites and closing or opening of them. The oral apparatus, composed of a membranous system and a pharyngeal basket, is an elaborate organelle. The membranous system shows such movement as seen in a sphincter muscle, moving the triangular trichites in a manner which opens or moving the triangular trichites in a manner which opens or closes the cytostome. Each of the triangular trichites is connected with the expanded end of a long trichite; together these structures, 11-13 in number, constitute the pharyngeal basket. The ridges, the long trichites and the semicircular trichites are composed of fibrillar elements, but their twisted figures may be produced artificially by staining methods. Binary fission of Chlamydodon pedarius, under natural conditions in the season from April to October, occurs daily during the period 11 a.m. to 4 p.m. Each of the fissions takes about 2 hours. In the first half of this fission time: the V-area consisting of four central ciliary systems gives rise to transitions in the arrangement of the ciliary rows and ridges on both its anterior and middle portions; the pharyngeal basket falls down into the cytoplasm; and rosettes appear in the above two fields. On the other hand, plasmotomy arises in a fission furrow from the right side of the fission line. In the second half of the fission process, the oral apparatuses develop from the rosettes, while the old basket is dissolved into the cytoplasm; and, as the fission furrow extends leftward, two transverse bands and the frontal pellicle of the posterior daughter ciliate are organized on the surface of the fission furrow.