. Elementary text-book of zoology. Zoology. ALIMEXTARY CANAL. 55 vascular canals). In the larger Polyps (Anthozoa) a tube derived from an invagination of the oral disc projects into the central part of the digestive cavity. This is known as the stomach of the polyp, although it serves entirely for the introduction of food, and should be called rather the buccal or cesophageal tube (fig. 43). Organs for the prehension of food are found even with this simple digestive system. For near the mouth are placed radially or bilate- rally arranged appendages or processes of the body, which set up. --EG
. Elementary text-book of zoology. Zoology. ALIMEXTARY CANAL. 55 vascular canals). In the larger Polyps (Anthozoa) a tube derived from an invagination of the oral disc projects into the central part of the digestive cavity. This is known as the stomach of the polyp, although it serves entirely for the introduction of food, and should be called rather the buccal or cesophageal tube (fig. 43). Organs for the prehension of food are found even with this simple digestive system. For near the mouth are placed radially or bilate- rally arranged appendages or processes of the body, which set up. --EG RK FIG. 41.—Aurelia aurita seen from the oral surface. MA, the four oral tentacles with the mouth in the centre ; Gk, genital folds; GH, opening of the genital pouches ; Jii-, mar- ginal bodies ; A'G, radial canals ; T, tentacles at the margin of tho disc. currents to convey small particles of food, or as tentacles seize foreign bodies and convey them to the mouth (Polyps, Medusae) (tig. 44). Such appendages serving for the capture of prey may also be placed further from the mouth (tentacles of Medussj, Siphonophora, Ctenophora). When tho digestive cavity acquires a wall distinct from the body wall, and usually separated from the latter by the body cavity (ex- cepting the parenchymatous worms), it appears in the simplest cases as a blind tube, which may be either simple, bifurcated, or branched. 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 Claus, Carl, 1835-1899; Sedgwick, Adam, 1854-1913; Sinclair, F. G. (Frederick Granville), b. 1858. New York : Macmillan
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectzoology, bookyear1884
