. Elementary text-book of zoology, tr. and ed. by Adam Sedgwick, with the assistance of F. G. Heathcote. NEMATODA. a Sc. tetraranthitm Mehlis, also in the intestine of the horse. The embryos, after migrating into the intestine, become encysted in the walls of the rectum and caecum, assume within the cyst their definite form, break out from the cyst, and escape again into the intestine. Gucullanns elegant Zed., in the Perch. Fam. Trichotrachelidae. with iong neck-like thin anterior portion of the body. Mouth small, without papillae. (Esophagus very long, traversing a peculiar cord of cells. Tri
. Elementary text-book of zoology, tr. and ed. by Adam Sedgwick, with the assistance of F. G. Heathcote. NEMATODA. a Sc. tetraranthitm Mehlis, also in the intestine of the horse. The embryos, after migrating into the intestine, become encysted in the walls of the rectum and caecum, assume within the cyst their definite form, break out from the cyst, and escape again into the intestine. Gucullanns elegant Zed., in the Perch. Fam. Trichotrachelidae. with iong neck-like thin anterior portion of the body. Mouth small, without papillae. (Esophagus very long, traversing a peculiar cord of cells. Triclioceplialus Goeze. Anterior part (fig. 285) of the body elongated and whip shaped: posterior part cylindrical and sharply distinct, enclosing the generative organs, in the male it is coiled up. Lateral lines absent. Main median lines present. The penis is slender and furnished with a sheath, which is turned inside out when the former is protruded. The hard-shelled, lemon-shaped eggs undergo the first part of their development in water. Tr. dispar Hud. In the human colon : these worms do not live free in the intestine, but bury their filiform anterior extremity in the mucous membrane (fig. \ C 285). The eggs pass out of the host with the feces, as yet without a sign of beginning development, which only takes place after a prolonged sojourn in the water or in a damp place. According to the ex- periments of Leuckart per- formed with Tr. affinis of the sheep and Tr. crcnatus of the pig, embryos with the egg membranes, if introduced into the intestine, develop into the adult Tricoceplialus; and we may therefore conclude that the human Tr. dispar is intro- duced directly, and without an intermediate host either in the drinking water or in uncleaned food. The young Tr. dispar is at first hair-like, and re- sembles a Trichina, and only gradually acquires the considerable thickness of the hind end of the body. Trichosomum Rud. Body thin, hair-like, but the posterior end of the body in
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