. Fresh-water biology. Freshwater biology. THE WATER FLEAS (CLADOCERA) 69s 29 (28) Rostrum and antennules pulex-Uke; post-abdomen tapered, not sinuate Daphnia psittacea (Baird) 1850. General form like D. magna but smaller and more trans- parent. Post-abdomen tapering, not sinuate, with about 10 anal teeth and many clusters of short, fine hairs. Claws with two pectens, the distal having about IS teeth. Length, 9 , to mm. besides spine of mm.; J, to mm. Nebraska, in pools. Fig. 1063. Daphnia psittacea, note small secondary fornix behind MM 30 (27) Secondary fornix rudim
. Fresh-water biology. Freshwater biology. THE WATER FLEAS (CLADOCERA) 69s 29 (28) Rostrum and antennules pulex-Uke; post-abdomen tapered, not sinuate Daphnia psittacea (Baird) 1850. General form like D. magna but smaller and more trans- parent. Post-abdomen tapering, not sinuate, with about 10 anal teeth and many clusters of short, fine hairs. Claws with two pectens, the distal having about IS teeth. Length, 9 , to mm. besides spine of mm.; J, to mm. Nebraska, in pools. Fig. 1063. Daphnia psittacea, note small secondary fornix behind MM 30 (27) Secondary fornix rudimentary or very small. rarely exceeding 10, usually fewer. Teeth of distal pecten 31 31 (32, 33) Ocellus present; head not helmeted. Daphnia pulex (de Geer) 1778. Body stout and heavy; usually not transparent. An- tenmiles very small, the apex appearing as papillae on pos- terior surface of rostrum. Post-ab- domen without sinus; anus at end; anal spines 12-17. Summer eggs numerous; ephippium with two eggs placed nearly vertically. Color red to yellow-brown, very variable. Length, 9 , to mm. In pools and lakes in all regions; numerous varieties. Fig. 1064. Daphnia pulex. D. pulex includes a great number of varieties, many of which have been de- scribed as distinct species. The student will be safe in assigning to pulex all opaque, heavy-bodied forms with pectinate claws. In many cases the identification of the variety is more important than that of the species, but the varieties have not been worked out for this country. A few may be noted:. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Ward, Henry Baldwin, 1865-1945; Whipple, George Chandler, 1866-1924. joint author. New York, John Wiley & sons, inc. ; [etc. ,etc. ]
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfreshwa, bookyear1918
