. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. STUDIES ON DALLASIA FRONTATA STOKES. 105 quently protrudes from the mouth (Fig. II., }. At the re- gion of the gullet and on the opposite side of the tongue is a long, narrow undulating membrane, the adoral membrane (Fig. II. }. From the base of this membrane to the gullet is a long ladder-like structure recalling the " railroad track " of Chlamy- dodon (). There is evidence of a complicated neuro-motor system which will be described in a later paper on the cytology of these forms. The macronucleus, like
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. STUDIES ON DALLASIA FRONTATA STOKES. 105 quently protrudes from the mouth (Fig. II., }. At the re- gion of the gullet and on the opposite side of the tongue is a long, narrow undulating membrane, the adoral membrane (Fig. II. }. From the base of this membrane to the gullet is a long ladder-like structure recalling the " railroad track " of Chlamy- dodon (). There is evidence of a complicated neuro-motor system which will be described in a later paper on the cytology of these forms. The macronucleus, like the organism, is polymorphic. In many individuals it appears to be emarginate, frayed out and of a de- A. m. B FIG. II. Mouth and buccal pouch of Dallasia frontata. A. Total preparation of tailed form; mouth and buccal pouch only. B. Transverse section of tailed form. , ladder; , adoral membrane; £./>., buccal pouch; , endoral membrane; mouth opening; T., tongue and supporting bars. cidedly unhealthy appearance. It is often splinter-like and irregu- lar, but at the approach of division it becomes more condensed and homogeneous and ellipsoidal in form. It divides without mitosis and in the characteristic manner of most macronuclei. The micronucleus is usually single, spherical, and homogeneous, and is closely applied to the macronucleus. It divides by mitosis. The contractile vacuole is a single vesicle, in the middle of the ventral surface; feeding canals are absent but a ring of feeding vesicles, clearly visible after contraction of the vacuole, are present. The cytoplasm is filled with great vacuoles which are frequently so abundant as to distort the organism. They are gastric vacuoles for the most part but are frequently merely fluid-filled 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 not perfectly resemble
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
