. Elementary text-book of zoology. Zoology. AMBULACRAL APPENDAGES. ALIMENTARY CANAL. 275 M. all cases serve for locomotion. In addition to the ambulacral feet, great tentacle-like tubes may be present as appendages of the water- vascular system; the circle of tentacles round the mouth of ffolo-t tlmrians (fig. 209) is composed of such appendages. We also find leaf-like appendages arranged over four or five-leaved rosette- shaped areas, forming the ambulacral gills of the Spatangidea and Clypeastridea (figs. 207 and 208). The irregular Sea-urchins all possess in addition ambulacral feet upon th
. Elementary text-book of zoology. Zoology. AMBULACRAL APPENDAGES. ALIMENTARY CANAL. 275 M. all cases serve for locomotion. In addition to the ambulacral feet, great tentacle-like tubes may be present as appendages of the water- vascular system; the circle of tentacles round the mouth of ffolo-t tlmrians (fig. 209) is composed of such appendages. We also find leaf-like appendages arranged over four or five-leaved rosette- shaped areas, forming the ambulacral gills of the Spatangidea and Clypeastridea (figs. 207 and 208). The irregular Sea-urchins all possess in addition ambulacral feet upon the ventral surface. These are in the Cly- j)eastridea ; almost mi- croscopic in size; they are very numerous, and are arranged in branched rows or are irregularly distributed over the surface. The Echinodermata possess an alimentary canal distinct from the body cavity; it can be divided into three parts—oesopha- gus, stomach, and rectum. The anus is placed usually at the. Wl &^ Cl centre of the apical pole, rarely in an inter- radius on the ventral side. The intestine may, however, end blindly, as for example in all the Ophiuridce and EuryaHln-', also in the genera Aster o- Ctenodiscus, and Liddia, which have no anus. The mouth FIG. 219.—Holothuria tululwa, opened longitudinally (after M. Edwards). O, Month in the midst of the tentacles (T) ; D. digestive canal; Sc, stone canal; P, Polian vesicle ; Kg, circular vessel of the water-vascular system ; Ov, ovaries; Ay, ambulacral vessel; J/, longitudinal muscles; Gf, vessel to the intestine; Cl, cloaca; If'/, respiratory 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
