. Text-book of zoology for junior students. Zoology. CRUSTACEA. 147 a sliield, or the animal may be enclosed within a bivalve shell. To this order belong the curious " Brine-shrimps " (Artemia), which are found in the brine-pans of salt-works, or in salt lakes. Okders CliVDocera, Copepoda, and Ostracoda. These orders deserve mention more from the extreme abundance of their commoner forms than for any other reason. They include a number of minute Crustaceans, most of which are commoidy called " Watei'-fleas," and which abound both in fresh and in salt water, in almost all re
. Text-book of zoology for junior students. Zoology. CRUSTACEA. 147 a sliield, or the animal may be enclosed within a bivalve shell. To this order belong the curious " Brine-shrimps " (Artemia), which are found in the brine-pans of salt-works, or in salt lakes. Okders CliVDocera, Copepoda, and Ostracoda. These orders deserve mention more from the extreme abundance of their commoner forms than for any other reason. They include a number of minute Crustaceans, most of which are commoidy called " Watei'-fleas," and which abound both in fresh and in salt water, in almost all regions of the glolje. They are, however, mostly so small that, though visible to the e}^e, they can only be satisfactorily examined under the microscope. As an example of the C'ladocera may be taken the " Branched-h(5rned Water-flea" (Daphnla pulex, fig. 97, 6), thousands of which may be captured in any pond in summer. In this pretty little species the whole body is enclosed in a bivalve shell, which is so transparent Jhat the whole organisation. -Frcsli-water Eutomostmca. a Cjii'V: c l.'il'.'loiis quadrico of the animal is clearly visible through it. The h'jad is distinct, and carries a single eye. The greater antemue are branched. The males are smaller than the females, and nuich fewer in numlier ; and it appears to be a well-estalilished fact that the female, when once fei-tilised by the male, can not only lay eggs for the rest of her life, but can transnut the power of producing fertile ova to her young for several genei-ations. Of the i'ofjepnda one of the commonest is the Ci/dops (fig. 97, c), in which the cei>halotli(>rax is covered by a shield, and there is a well-developed abdomen. The female carries on either side a kind of pouch or ovisac, in which the eggs remain till they hatched. The little Ostracoda (tig. 97, a), are all minute. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readabilit
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectzoology, bookyear1885
