. Elementary text-book of zoology, general part and special part: protozoa to insecta. Animals. GJarUYEEA. 389. the female of Bondlia have the same relations (fig. 313). These rudimentary males are furnished (in many species) with two ventral hooks, in front of which in the anterior region is placed the external opening of the vas deferens. The vas deferens corresponds to the uterus of the female, and is in like manner provided with an internal opening into the body c;ivity. In Echiurus there are two pairs of brov/n tubes, which function as generative ducts and reservoirs. In Thcda
. Elementary text-book of zoology, general part and special part: protozoa to insecta. Animals. GJarUYEEA. 389. the female of Bondlia have the same relations (fig. 313). These rudimentary males are furnished (in many species) with two ventral hooks, in front of which in the anterior region is placed the external opening of the vas deferens. The vas deferens corresponds to the uterus of the female, and is in like manner provided with an internal opening into the body c;ivity. In Echiurus there are two pairs of brov/n tubes, which function as generative ducts and reservoirs. In Thcdassema there are, according to Kowalevski, thi-ee pairs of such tubes. The development shows many points of similarity with that of the Annelida. Be- tween the Achceta and Chcetifera, however, thei'e are considerable differences. In both cases a metamorphosis follows the embryonic development. The larvae resemble Loven's larva (larva of Polygordius); but in the Achceta they are characterised by a great de- generation of the apical region (pi-aeoral lobe) and the absence of a prseoral band of cilia. The remarkable larva known as Actino- trocha, which is the young stage of the tubicolous genus Phoronis* is distinguished by the possession of a contractile prseoral lobe, behind which there is a circle of ciliated ten- tacles forming a collar. The Gephyrea are all marine. Some of them live in sand and ooze at considerable depths, also in holes in the rocks and in crevices between stones and corals, and in the shells of snails. Their food is similar to that of Hoiothurians and many tubicolous 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; Metcalf Collection (North Carolina State University). NCRS. London, Swan Sonnenschein
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectanimals, bookyear1892
