. A textbook of invertebrate morphology [microform]. Invertebrates; Morphology (Animals); Invertébrés; Morphologie (Animaux). TTPE NEMATEELMINTHES. 177 tlie diai»hragm, partly by the lymphatic and blood vessels, and partly by active migration in the connective tissue. The young Trichince measure about mm., and duiinjr their i)assage into the substance of the tiicy prodi more or less .severe inrtaniinatory disturbances. Having reached the muscle tissue they become encysted therein (Fig. 89, A), the cysts measuring about mm. in length, and if the disturbances which they produce
. A textbook of invertebrate morphology [microform]. Invertebrates; Morphology (Animals); Invertébrés; Morphologie (Animaux). TTPE NEMATEELMINTHES. 177 tlie diai»hragm, partly by the lymphatic and blood vessels, and partly by active migration in the connective tissue. The young Trichince measure about mm., and duiinjr their i)assage into the substance of the tiicy prodi more or less .severe inrtaniinatory disturbances. Having reached the muscle tissue they become encysted therein (Fig. 89, A), the cysts measuring about mm. in length, and if the disturbances which they produce have not proved fatal to the host the danger is past, the en- capsuled Trichina undergoing no further development within this host, tliough they may retain (heir vitality for many years. Other forms which o. ir in man are Ascaris lumhricoides, the round- worm (Fig. 88, B), a large form, of which the female measures 40 cm. in Icnglh and the male 25 cm., and which bears some resemblance in shape to an earth-worm, Oxyurisvermiculans, asmaller form, 1 cm. in length, which inhabits the rectumespecially of young children, and Trichocephaiusdispar (Fig. 88), which measures 3-5 cm. in length and is characterized by the anterior half of the body being exceedingly slender, the worm boring into the intestinal wall, especially in the neighboihood of the caecum, by this slender portion, the hinder thicker por- tion hanging freely in the wall of the intestine. The presence of these three forms may be recognized, independently of the finding of the actual worm, by tlieir ova, whose respective characters dif- fer very greatly. So far as is known the development of these forms is direct and there is no intermediate host, but the ova are tjikc-n into the body with the food. I' uneleanliiiess and imperfect drinking-water may be causes of infection. In addition to the forms which have t)een mentioned there arc a few which are more especially frc(iuent in tropical cli- mates. ^ocAm/,.sw
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Keywords: ., bookcentury1800, bookdecade1890, bookpublishernewyo, bookyear1896
