. Introduction to zoology; a guide to the study of animals, for the use of secondary schools;. FIG. 140. — Serpula tube on a bit of oystershell that is perforated by the boring tube lies in the centre of the size. Photo, by W. H. C. P. 152 ZOOLOGY B. FIG. 141. — Trichina. A, encysted form in muscle of pork; B, female;(, male; bh, envelope of cyst; cy, cyst; de, male duct; e, embryos; /, fatglobules; h, testis; mf, muscle fibre; oe, pharynx; ov, ovary; no, openingto egg duct; zh, cell masses in intestines. After Clans. NEREIS AND ITS ALLIES 153 T) pin-worm of man. Others
. Introduction to zoology; a guide to the study of animals, for the use of secondary schools;. FIG. 140. — Serpula tube on a bit of oystershell that is perforated by the boring tube lies in the centre of the size. Photo, by W. H. C. P. 152 ZOOLOGY B. FIG. 141. — Trichina. A, encysted form in muscle of pork; B, female;(, male; bh, envelope of cyst; cy, cyst; de, male duct; e, embryos; /, fatglobules; h, testis; mf, muscle fibre; oe, pharynx; ov, ovary; no, openingto egg duct; zh, cell masses in intestines. After Clans. NEREIS AND ITS ALLIES 153 T) pin-worm of man. Others still penetrate into the mus-cles, and cause great pain and often death. Such is thepork-worm, Trichina,1 which gets into man through un-cooked pork, multiplies in thefood canal, migrates in greatnumbers into the muscles andencysts itself there (Fig. 141).Another group which islargely parasitic is that of theflatworms. Some flatwormslive free in ponds. They willbe found abundantly amongplants taken from small pondsin the summer and autumn, andare commonly known as Pla-naria2 (Fig. 142). They maybe recognized not only by theirflattened form, but also by acurious proboscis which pro-trudes from the middle of theunder side of the body and bears «/ mouth at its tip.
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectzoology, bookyear1900
