. A manual of elementary zoology . Zoology. 302 MANUAL OF ELEMENTARY ZOOLOGY 1. Free-living throughout life.âThe Vinegar Worm, Anguillula aceti, found in vinegar. Rhabditis, in soil. 2. Free as larva, parasitic in plants as adults.âThe Cockle Worm, Tylenchus scandens, cause of " ear-cockles " in corn. Small worms from the soil wriggle up the stems of young corn plants, pair in the flowers when these form, cause galls to arise in place of grains, and lay eggs, from which hatch larvae. These can survive dry for twenty years but in damp earth become active. 3. Free as larva, parasitic i
. A manual of elementary zoology . Zoology. 302 MANUAL OF ELEMENTARY ZOOLOGY 1. Free-living throughout life.âThe Vinegar Worm, Anguillula aceti, found in vinegar. Rhabditis, in soil. 2. Free as larva, parasitic in plants as adults.âThe Cockle Worm, Tylenchus scandens, cause of " ear-cockles " in corn. Small worms from the soil wriggle up the stems of young corn plants, pair in the flowers when these form, cause galls to arise in place of grains, and lay eggs, from which hatch larvae. These can survive dry for twenty years but in damp earth become active. 3. Free as larva, parasitic in animals as adults. âThe Miners' Worm, Ancylostomum duodenale, of a pink colour, the male 8-11 mm. long, the female 10-18 mm., lives and pairs in the small intestine of Fig. 210.âThe Vinegar Worm (Anguillula aceti), somewhat dia- grammatic, to show arrangement of organs. A, Male; B, female. tâ Anus ; e., excretory pore ; , genital opening ; int., intestine ; , bulb of oesophagus ; mi., ovary ; , penial setae ; ph., pharynx ; ;â ., testis ; ut., uterus ; , vas deferens. Eggs are passed with the feces of the host and hatch in warm, damp places, but are killed by drought or frost. The little, thread-like laroe pierce the human skin, usually on the foot, hand, or mouth, enter venules, and are carried through the heart to the lung wall, which they penetrate. Thence they reach the gut by way of the glottis. Browsing on the villi, they cause intestinal haemorrhage, and thus aneemia, often fatal. The worm is widespread in warm countries, but elsewhere can exist only where the conditions are favourable, as in mines in Britain. Strict sanitation is necessary for avoiding its ravages. Male fern and thymol are the principal vermifuges used against it. 4. Larva: parasitic, adults free. â The Rain Worm, Mermis. nigrescens, whose larvse bore through the skin of young grasshoppers. Please note that these images are extracted from scanned page images that may ha
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectzoology, bookyear1920
