. Fresh-water biology. Freshwater biology. i8 (9) Head region distinct from rest of bodjf. Stenostomum coluber Leydig 1854. Length 6 mm. Width about one-thirtieth the length. Very slender, white, thread-like with snake-like movements. Head region broader than the rest of the body with blunt point at anterior end. Posterior end abruptly rounded. Asexual reproduction not known. Brackish water, Falmouth, Mass. Fro. 597. Stenoslomum coluber. Anterior end: m, mouth; ^A, pharynx; in, intestine; ov, egg (?); ns, protonephridium. X 20. (After Leydig.) * (8) Ciliated pits shallow. A club-shaped probosc
. Fresh-water biology. Freshwater biology. i8 (9) Head region distinct from rest of bodjf. Stenostomum coluber Leydig 1854. Length 6 mm. Width about one-thirtieth the length. Very slender, white, thread-like with snake-like movements. Head region broader than the rest of the body with blunt point at anterior end. Posterior end abruptly rounded. Asexual reproduction not known. Brackish water, Falmouth, Mass. Fro. 597. Stenoslomum coluber. Anterior end: m, mouth; ^A, pharynx; in, intestine; ov, egg (?); ns, protonephridium. X 20. (After Leydig.) * (8) Ciliated pits shallow. A club-shaped proboscis is present. Khynchoscolex. Only one species Khynchoscolex simplex Leidy 1851. Length 4 to 7 mm. Color yellowish-white opaque. Anteriorly abruptly attenuated into a long cylindrical clavate proboscis; anterior end abruptly narrowed, obtusely rounded. Pro- boscis shows longitudinal and numerous transverse marks. Mouth ventral, at the base of the proboscis. Intestine straight and capacious. A small wriggling worm found among yellowish fragments of vegetable matter and confervae at the bottom of clear brooks in the vicinity of Philadelphia. Von Graff regards the European species R. vejdovski Sekera 1888 as probably identical with this American form. 20 (s) With two lateral branches of the protonephridium. Family Microstomidae . 21 Mouth a longitudinal slit on ventral surface, intestine occasionally with side lobes. Proto- nephridial branches open in anterior end. Testes and ovaiy either paired or unpaired, with two ventral sexual pores, the male posterior to the female. With or without eyes and cihated pits. 21 (24) The intestine extends dorsally and anteriorly beyond the junction with the pharynx Subfamily Microstominae. Only one genus Microstomum . 22 22 (23) With two reddish-yellow pigmented eye spots. Microstomum lineare (Miiller) Length of single individuals mm. In chains up to 18 zooids with a length of 9 to 11 mm. Slender. Very active. Color yellowish to grayis
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfreshwa, bookyear1918
