. The Cambridge natural history. Zoology. 142 PROTOZOA protoplasm it has a honeycombed or alveolate structure, but in this case the alveoli are permanent in their arrangement and position. Eows of these alveoli run under the surface; and the cilia are given off from their nodal points where the vertical walls of several unite, and wherein the basal granule or blepharo- plast is contained. Longitudinal threads running along the inner walls of the alveoli of the superficial layer are differen- tiated into muscular fibrils or " rayonemes," to which structures mi 'â â¢â¢â¢â¢/?â '⢠&
. The Cambridge natural history. Zoology. 142 PROTOZOA protoplasm it has a honeycombed or alveolate structure, but in this case the alveoli are permanent in their arrangement and position. Eows of these alveoli run under the surface; and the cilia are given off from their nodal points where the vertical walls of several unite, and wherein the basal granule or blepharo- plast is contained. Longitudinal threads running along the inner walls of the alveoli of the superficial layer are differen- tiated into muscular fibrils or " rayonemes," to which structures mi 'â â¢â¢â¢â¢/?â '⢠&. a Fig. 50.âEctosarc of Ciliata. a-f, from Stciitor coeruleus ; g, Holophrya discolor, a. Transverse section, showing cilia, pellicle, canals, and myonemes ; b, surface view below pellicle, showing uiyoiiemes alternating with blue grannlar streaks ; c, n)ore superScial view, showing rows of cilia adjacent to myonemes ; d, myoneme, highly magniKed, showing longitudinal and transverse striation ; e, two rows of cilia ; /, g, optical sections of ectosarc, sliowiug pellicle, alveolar layer (a), myonemes (m), and canals in ectosarc. (From Calkins, after Metschnikoff, Biitschli, and Johnson.) so many owe their marked longitudinal striation on the one hand, and their power of sudden contraction on the other. The appearance of transverse striation may be either due to transverse myonemes, or produced by the folds into which the contraction of longitudinal fibrils habitually wrinkles the pellicles, when it is fairly dense (Peritrichaceae); circular muscular fibrils, however, undoubtedly exist in the peristomial collar of this group. Embedded in the ectosarc are often found trichocysts/ analogous ' See Mitrophanow " Sur les Tnchocystes . . du Paramoecium," Arch. Protist. V. 1904, p. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may n
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