. Elementary text-book of zoology. Zoology. CIRRIPEDTA. 441 Lepadid(f and the Bcdunidce, the alimentary canal consists of a nai-row oesophagus, a saccular dilated stomach provided with several caecal (hepatic) diverticula, an elongated chyle-forming intestine, and a short rectum, which is only sometimes clearly marked off from the intestine (fig. 349). The Rlnzoceplmla (fig. 354, a), which are with- out an alimentary canal, possess root-like processes of the paren- chyma, which ramify in the viscera, especially the liver of Decapods, and absorb from them endosmotically the nutritive "juic
. Elementary text-book of zoology. Zoology. CIRRIPEDTA. 441 Lepadid(f and the Bcdunidce, the alimentary canal consists of a nai-row oesophagus, a saccular dilated stomach provided with several caecal (hepatic) diverticula, an elongated chyle-forming intestine, and a short rectum, which is only sometimes clearly marked off from the intestine (fig. 349). The Rlnzoceplmla (fig. 354, a), which are with- out an alimentary canal, possess root-like processes of the paren- chyma, which ramify in the viscera, especially the liver of Decapods, and absorb from them endosmotically the nutritive "juices (as in Anelasma). Special glandular organs, the so-called cement glands (peculiar to the Cirripedia), open on the sucker of the persistent (anterior) antenna;: the animal is fixed by their secretion, and the Rhizocephala alone seem to be en- tirelv without v r « them. A heart and vascular sys- tem seem to be wanting in all cases. The tubes which are present on seve- ral thoracic ap- pendages o f m: i ny Lepadidce are regarded as branchiae, as are also two plicated lamel- la? on the inte- rior of the mantle of the Balanidce. Generative organs.—The Cirripedia are, with a few exceptions, hermaphrodite. The testes are branched glandular tubes, and lie at the sides of the alimentary canal (fig. 349, T). The vasa deferentia which dilate into vesicular seininales reach to the base of the cirri- forrn penis, in which they unite to form a common ductus ejacula- torius opening at the point of the penis (IV). The ovaries in the Balanidce lie in the basal part of the body cavity (fig. 348, Or) ; in the Lepadidce (fig. 349) they are moved into the prolongation of the head, which is known as the stalk. The oviducts, according to. FIG. 350.—Alci/i/if lamjias (after Ch. Darwin.) a, Male, very strongly magnified; A', antenna?; T, testis ; I'», seminal vesicle ; D, redu- plicative of the skin; 0, eye; P, penis. 6, Longitudinal section through female; F, maxilliped; Cf, the three pairs o
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectzoology, bookyear1884
