. A manual of elementary zoology . Zoology. 186 MANUAL OF ELEMENTARY ZOOLOGY oblong gullet are two grooves, the siphonoglyphs, down one of which and up the other currents of water flow even when the rest of the mouth is closed. As in Hydra, the tentacles are hollow and there is no medusa, though a planula larva is found. Corals are related to anemones, but secrete a calcareous shell or skeleton on the surface of the ectoderm of the lower part of the body. Thus the. Fig. iiS.—A small specimen of the Common Jelly-fish. Aurelia aitriht, natural size. Note the horseshoe-shaped gonads, showing thro
. A manual of elementary zoology . Zoology. 186 MANUAL OF ELEMENTARY ZOOLOGY oblong gullet are two grooves, the siphonoglyphs, down one of which and up the other currents of water flow even when the rest of the mouth is closed. As in Hydra, the tentacles are hollow and there is no medusa, though a planula larva is found. Corals are related to anemones, but secrete a calcareous shell or skeleton on the surface of the ectoderm of the lower part of the body. Thus the. Fig. iiS.—A small specimen of the Common Jelly-fish. Aurelia aitriht, natural size. Note the horseshoe-shaped gonads, showing through the transparent tissues ; the radial canals, alternately branched anil unliranched : the little sense tentacles in notches each opposite the middle branch of a canal ; the marginal tentacles ; and the arms of the manubrium, each folded ami fringed. " coral insect" is a polyp. The large jelly-fish (Aca/ep/nc) differ from the little medusae of the hydroids in having no velum or nerve ring, and developing their generative cells on the endoderm of the stomach wall ; their radial canals are often branched. Under the four generative organs lie sul'gemla/pits of the subumbrella ectoderm. When "there is a polyp generation (Hydra tuba), it has hollow tentacles, four. 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 Borradaile, L. A. (Lancelot Alexander), 1872-1945. London : H. Frowde, Hodder & Stoughton
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectzoology, bookyear1920
