. Elementary text-book of zoology, general part and special part: protozoa to insecta. Animals. KEMATODA. 351 to be the lateral surfaces of the moving animal. Most JSfematoda are parasitic, but lead an independent life in certain stages of their life history. Numerous small Nematoda, however, are never parasitic, but live freely in fresh and salt water and in the earth. Some Nematodes are parasitic in plants, for example, Anguillula tritici, dipsaci, etc.; some live in decaying vegetable matter, , the vinegar worm in fermenting vinegar and paste. Nevertheless very similar forms occur in th
. Elementary text-book of zoology, general part and special part: protozoa to insecta. Animals. KEMATODA. 351 to be the lateral surfaces of the moving animal. Most JSfematoda are parasitic, but lead an independent life in certain stages of their life history. Numerous small Nematoda, however, are never parasitic, but live freely in fresh and salt water and in the earth. Some Nematodes are parasitic in plants, for example, Anguillula tritici, dipsaci, etc.; some live in decaying vegetable matter, , the vinegar worm in fermenting vinegar and paste. Nevertheless very similar forms occur in the contents of the intestine and in the faeces of different animals and of man {A. intestinalis, stercoralis). The power possessed by small Nematoda of resisting the effects of pro- longed desiccation and of coming to life again on being moistened is very remarkable. Fam. Ascaridae. Body tolerably stout. With three lips furnished with papillte. One of these lips is,directed towards the dorsal surface, while the two others meet together in the ventral line. The posterior end of the male is ventrally curved, and usually furnished with two horny Fig. 283.—^»cari« lumbricoides (after R. Leuckart). a, Posterior end of a male with the two spicula (Sp). b. Anterior end from the dorsal side, with the dorsal Up furnished with two papillae, c. The same from the ventral side with the two lateral ventral lips and the excretory pore (P). d. Egg with the external membrane formed of small clear spherules. Ascaris L. Polymyarian, with three strongly developed lips, the edges of which are in the larger species pi'ovided with teeth. The pharynx is not sepa- rated as a distinct bulb. The caudal extremity is usually short and conical, and in the male sex invariably provided with two spicula (fig. 283, a). A. lumbricoidcs Cloquet, the human round worm, a smaller variety in the pig (j1. suilla Duj.) The eggs pass into water or damp earth and remain there some months, until the embryonic
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectanimals, bookyear1892
