. Fresh-water biology. Freshwater biology. THE WATER FLEAS (CLADOCERA) 693 18 (3) Enclosed in gelatinous mantle. Antennae simple in female, cylindrical, with 3 terminal setae Family Holopedidae Sars. Animal enclosed in a large, globular, transparent, delicate but tough, gelatinous case, open ventrally and forming 2 valves. Body much compressed, shell of head and body very thin and high, as seen from side, leaving uncovered the mouth parts, the ends of the feet, and the hind part of body. Antennule small, fixed; with 5-6 olfactory setae and lateral sense-hair, but no flagellum. Antennae in 9 lo
. Fresh-water biology. Freshwater biology. THE WATER FLEAS (CLADOCERA) 693 18 (3) Enclosed in gelatinous mantle. Antennae simple in female, cylindrical, with 3 terminal setae Family Holopedidae Sars. Animal enclosed in a large, globular, transparent, delicate but tough, gelatinous case, open ventrally and forming 2 valves. Body much compressed, shell of head and body very thin and high, as seen from side, leaving uncovered the mouth parts, the ends of the feet, and the hind part of body. Antennule small, fixed; with 5-6 olfactory setae and lateral sense-hair, but no flagellum. Antennae in 9 long; basal joint curved, annulated; the single ramus 2-jointed; antennae of $ biramous. Post-abdomen large, fleshy, not bent forward; with rather long, curved anal spines and clusters of very fine spinules; abdominal setae long, set on single, long, conical projection. Claws large, curved, denticulate, not set off from body by distinct joint. Eye small, with numerous lenses; ocellus small. Intestine simple with 2 hepatic ceca. Branchial sac on second to fifth feet. Color transparent. Swims on its back. Sole genus with characters of family. Holopedium Zaddach 1855 . 19 19 (20) Ventral margins of valves with fine spines. Holopedium gibberum Zaddach 1855. Post-abdomen elongated (ca. one-third length of body) and tapering; anal spines nimierous, up to 20. Claws with i basal spine. Length, J, nun.; J, mm. This remarkable and beautiful species is not uncommon in open water in northern lakes; has been found in the Great Lakes, and in many inland waters, both lakes and smaller bodies of water. Figs. 1060, 1061, a. Holopedium gibberum (gelatinous case not shown). (See also Fig. 1061.) 20 (19) Ventral margin of valves smooth. Holopedium amazonicum Stingelin 1904, Post-abdomen short, blunt (ca. one-fourth of body in length), with 7-8 anal spines, the row continued forward by 3-4 very small spinules. Claws without basal spine. Abdom- inal setae very long and 3-joint
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfreshwa, bookyear1918
