. Fresh-water biology. Freshwater biology. FREE-LIVING NEMATODES 483 r .9 8. 13 -61 '2,2 93 \ .8 —' 2^ c- .9 Mr- -M 2.' 93. ,6 (7) Esophagus with a distinct median bulb, and a more or less distinct posterior swelling. Males with bursa. Tylenchus Bastian. Genus consisting of numerous species, many of them parasitic in plants and sometimes highly injurious. Aquatic species are rather uncommon. A single species found parasitic in a marine alga. Principally owing to its economic importance the genus has a very extensive literature. Representative species. Tylenchus dipsaci Kiihn 1857.
. Fresh-water biology. Freshwater biology. FREE-LIVING NEMATODES 483 r .9 8. 13 -61 '2,2 93 \ .8 —' 2^ c- .9 Mr- -M 2.' 93. ,6 (7) Esophagus with a distinct median bulb, and a more or less distinct posterior swelling. Males with bursa. Tylenchus Bastian. Genus consisting of numerous species, many of them parasitic in plants and sometimes highly injurious. Aquatic species are rather uncommon. A single species found parasitic in a marine alga. Principally owing to its economic importance the genus has a very extensive literature. Representative species. Tylenchus dipsaci Kiihn 1857. I i mm. This species is found parasitic in onion and hya- mm. cinth bulbs, and in a num- ber of other plants, and is very harmful. The spear, J, i. Fig. II, is shot forth by the muscles, /, and is used to puncture the cells of the host plant. The spear is tubular, and the juices of the host are sucked through the spear into the intestine by means of the bulb, c. Often referred to in literature as Tylenchus devastatrix. Habitat: Europe, America, Australia, and probably throughout the temperate regions. Fig. 776. Tylenchus dipsaci. Kuhn. I, a female; II, head of the same more highly magnified; III, tail of a male; IV, view from below, of the female sexual opening; V, cross- section of the neck passing through the median sucking-bulb; VI, front view of the penes and their accessory parts; VII, cross-section through the middle of a female, showing how the body-cavity is filled completely by the ovary (w) and the intestine iz). a, lip region; ft. tip of spear; c, median sucking-bulb; d, nerve-ring; e, excretory pore; /. muscles for moving the spear forward; g, posterior esophageal swelling; h, excretory gland; i, hind end of spear, thtee-bulbed: j, loop in ovary; k, right spiculura; I, muscles for opening the vulva; m, the vulva; n, glandular (?) bodies; o, bursa; p, hmd end of ovary; q, uterus containing spermatozoa and one segmenting egg; r, segmenting egg: s. vagina; t, the
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfreshwa, bookyear1918
