. Comparative zoology, structural and systematic. For use in schools and colleges. Zoology. 112 COMPARATIVE ZOOLOGY. water. This may be called the "water- pipe ; Besides this, there are nu- merous gill-like fringes, which probably'" aid in respiration. Fresh-water Worms,- like the Leech and Earth-worm, breathe by the skin. The body is always covered b}' a viscid fluid, which has the property of absorbing air. The air is, therefore, brought into immedi- ate contact with the soft skin, underneath which lies a dense net-work of blood-ves- sels. All the rest of water-breathin
. Comparative zoology, structural and systematic. For use in schools and colleges. Zoology. 112 COMPARATIVE ZOOLOGY. water. This may be called the "water- pipe ; Besides this, there are nu- merous gill-like fringes, which probably'" aid in respiration. Fresh-water Worms,- like the Leech and Earth-worm, breathe by the skin. The body is always covered b}' a viscid fluid, which has the property of absorbing air. The air is, therefore, brought into immedi- ate contact with the soft skin, underneath which lies a dense net-work of blood-ves- sels. All the rest of water-breathing animals have gills. The simplest form is seen in Marine Worms: delicate veins projecting through the skin make a series of arbores- cent tufts along the side of the body ; as these float in the water, tlie blood is puri- n fled. Bivalve Mollusks have four flat gills, {Armuoiapiscato- eoiisisting of dclicatc memi)ranes flUed with ruvi), a clorsibrau- » chiate, showing blood-veSSols the tufts of capil- laries, or external and covered gills. The large . , ... y head is without '^Vltll Cilia. in eyes or jaws. the OystCr, those ribbon-like folds are exposed to the water when the shell opens; but in the Clam, the mantle incloses them, forming a tube, called siphon^ through which the water is di-iven by the ; The aquatic Gas- Fig. section of a teronods <'TTT1ivnlvPS^ hnvP LamellibranchUnor/o/O: «, lobes of leiOpOUS (^Uni\ai\eSj na\e mantle; , sho«iug transverse either tufts, like the Worms, P«miions; c, ventricle of heart; d, _ _ _ _ _ auricles; , pericardium;/, <7, gland- Or comb-like ciliated gills in ular sacs; /), venous sinus;'fc, foot; , . ^ A, branchial, or iiallial, chamber; B, a cavity beluild tJie head, to eplbranchlal 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 th
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Keywords: ., bookcentury1800, bookdecade1880, bookpublishe, booksubjectzoology
