. A manual of zoology. Zoology. PLATHELMINTHES 239 is composed of a solid parencJiyvta, a mass of connective tissue traversed by muscle fibres, in which the various organs—alimentary tract, ner\'es, excretory and reproductive organs—are imbedded. The digestive. Fig. 212.—Transverse section (rit;ht half) of a Planarian. d, vitellaria; dv, dorso- ventral muscle fibres; e, ectodermal epithelium with cilia; g, gastric diverticula; h, testicular follicles; Im, longitudinal muscles (dots, in section); n, lateral nerve cord. system has various shapes; in the lower groups it resembles that of the ccel
. A manual of zoology. Zoology. PLATHELMINTHES 239 is composed of a solid parencJiyvta, a mass of connective tissue traversed by muscle fibres, in which the various organs—alimentary tract, ner\'es, excretory and reproductive organs—are imbedded. The digestive. Fig. 212.—Transverse section (rit;ht half) of a Planarian. d, vitellaria; dv, dorso- ventral muscle fibres; e, ectodermal epithelium with cilia; g, gastric diverticula; h, testicular follicles; Im, longitudinal muscles (dots, in section); n, lateral nerve cord. system has various shapes; in the lower groups it resembles that of the ccelenterates in that there is but a single opening and this leads by an ectodermal oesophagus (stomodaeum) to the interior (fig. 59). In parasites the digestive tract may be lost. The skin is a one-layered epithelium, sometimes cili- ated, sometimes protected by a thick cuticula. Inside this comes a muscular layer (fig. 212) in which longitudinal muscles are always present, and in addition frequently circular and oblique muscles, as well as those passing from dorsal to. 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
