. A manual of zoology. Zoology. III. CESTODA formation of numerous daughter bladders produces marked tumors in the liver of man and domestic animals, before the formation of scolices begins. In the interior of each daughter vesicle appear a number of brood vesicles, each of which produces numbers of scolices, so that from a single six-hooked embryo thousands of scolices can arise (fig. 232). In contrast to this extreme case are others which connect with the development of Bothriocephalus, in which the cysticercus is replaced by a cysticercoid (fig. 231). Here there is no infiltration and
. A manual of zoology. Zoology. III. CESTODA formation of numerous daughter bladders produces marked tumors in the liver of man and domestic animals, before the formation of scolices begins. In the interior of each daughter vesicle appear a number of brood vesicles, each of which produces numbers of scolices, so that from a single six-hooked embryo thousands of scolices can arise (fig. 232). In contrast to this extreme case are others which connect with the development of Bothriocephalus, in which the cysticercus is replaced by a cysticercoid (fig. 231). Here there is no infiltration and the scolex is closely enclosed by an envelope comparable to the bladder wall. In several cysticercoids a caudal appendage recalls the cercaria. The development of a tapeworm was earlier believed to be a complicated alternation of generations; the bladder to be a stage which by budding produced scolices; the scolex, in turn, a stage which by terminal budding produced the sexual animals, the proglottids, and the tapeworm itself a chain of individuals, a strobila. This view, so easy to learn, contains two errors. The bladder is not an independent generation, but only the hinder end of the scolex. The tapeworm is not a colony, but a single animal; the proglottids are not individuals, but specialized parts of a whole. This view is confirmed by a comparison with other forms. The Caryophyllfeidas (fig. 233) are single bodies, the anterior end. 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 Hertwig, Richard, 1850-1937; Kingsley, J. S. (John Sterling), 1854-1929, ed. and tr. New York, H. Holt
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1912
