. Elementary zoology. Zoology. 7 6 ELEMENTARY ZOOLOGY the thickened, bent-out, upper margin of the bell. This margin is called the peristome. With what is it fringed ? The free end of the bell is nearly filled by a central disk, the epistome, with arched upper surface and a circlet of cilia. Between the epistome and peristome is a groove, the mouth or vestibule, which leads into the body. Study the internal structure of the transparent, bell- shaped body. Note the differentia- tion of the protoplasm comprising the body into an inner transparent color- less endosarc containing various dark- col
. Elementary zoology. Zoology. 7 6 ELEMENTARY ZOOLOGY the thickened, bent-out, upper margin of the bell. This margin is called the peristome. With what is it fringed ? The free end of the bell is nearly filled by a central disk, the epistome, with arched upper surface and a circlet of cilia. Between the epistome and peristome is a groove, the mouth or vestibule, which leads into the body. Study the internal structure of the transparent, bell- shaped body. Note the differentia- tion of the protoplasm comprising the body into an inner transparent color- less endosarc containing various dark- colored granules, vacuoles, oil-drops, etc., and an outer uniformly granular ectosarc not containing vacuoles. Is the stalk formed of ectosarc or en- dosarc or of both ? Note the curved nucleus lying in the endosarc. (This may be difficult to distinguish in some specimens.) Note the numerous large circular granules, the food vacuoles. Note the contractile vesicle, larger and clearer than the food vacuoles. Note the thin cuticle lining the whole body externally. A high magnification will show fine trans- verse ridges or rows of dots on the cuticle. Make a drawing showing the internal structure. Observe a living specimen carefully for some time to determine all of its movements. Note the contraction and extension of the stalk, the movements of the cilia of peristome and epistome, the flowing or streaming of the fluid endosarc (indicated by the movements of the food vacuoles), the behavior of the contractile sp. FlG. 8.— Vorticella one individual with stalk coiled, and one with stalk extended. (From life:). 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 the original Kellogg, Vernon L. (Vernon Lyman), 1867-1937. New York : H. Holt and company
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectzoology, bookyear1902
