. The life of inland waters; an elementary text book of fresh-water biology for American students. Freshwater biology. i88 Aquatic Organisms Fig. 94. An Ostracod {Cypris virens), lateral and dorsal views, (after Sharpe.) Some Ostracods are free- swimming (species of Cypris, etc.) and some {Notodromas) haunt the surface in sum- mer; but most are creeping forms that live among water plants or that burrow in the bottom ooze. In pools where such food as algas and decaying plants abound Ostracods frequently swarm, and appear as a multitude of moving specks when we look down into the still water. Re
. The life of inland waters; an elementary text book of fresh-water biology for American students. Freshwater biology. i88 Aquatic Organisms Fig. 94. An Ostracod {Cypris virens), lateral and dorsal views, (after Sharpe.) Some Ostracods are free- swimming (species of Cypris, etc.) and some {Notodromas) haunt the surface in sum- mer; but most are creeping forms that live among water plants or that burrow in the bottom ooze. In pools where such food as algas and decaying plants abound Ostracods frequently swarm, and appear as a multitude of moving specks when we look down into the still water. Relicit pools in a dry summer are likely to be found full of them. Both sexes are constantly present in most species of Ostracods, but a few species are repre- sented by females only, and reproduce by means of unfertilized eggs. The Copepods are the perennial entomostraca of open water. Summer and winter they are present. Three of the commonest genera are shown in figure 95, toge- ther with a naupliusâ-the larval form in which the members of this group hatch from the egg. Nothing is more familiar in laboratory aquaria than the little white Cyclops (fig. 96, swim- ming with a jerky motion, the female carrying two large sacs of eggs. A more or less pear-shaped body tapering to a bifurcate tail at the rear, a single median eye and a pair of large swimming antennae at Fig. 95. Common copepods the front, and fouT pairs of 'â ?u"sfS!=a^n^XT?£r^k)''oTc°;c!oZ thoracic swimming feet Figures e and / show females bearing egg "U ââ â â --u â -^ ^x.^-: â^ ^ sacs, while the detached antenna at the UCliCcttll, V^lidi ct\^ tCi iZ(C; bXlc; ii?th/mT.*''°"" °' *''"' ^'"''"''"^' members of this 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 Needham, Ja
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfreshwa, bookyear1915
