. Biology and human life. Biology. W I ,",i'<-.,\,' /â , 'â , I' . Fig. i86. How the haddock breathes In the fishes the gills are arranged on arches along both sides of the pharynx. Water is taken through the mouth and passes over the gills and out again, as indicated by the arrows. In the bony fishes the gill slits are covered by a shieldlike plate, the opcrcuhnn, which is free on the posterior edge. The bony fishes also have a swim- ming bladder, connected with the pharynx (see Fig. 78), which is apparently used partly for breathing (the blood vessels in the wall of the bladder be
. Biology and human life. Biology. W I ,",i'<-.,\,' /â , 'â , I' . Fig. i86. How the haddock breathes In the fishes the gills are arranged on arches along both sides of the pharynx. Water is taken through the mouth and passes over the gills and out again, as indicated by the arrows. In the bony fishes the gill slits are covered by a shieldlike plate, the opcrcuhnn, which is free on the posterior edge. The bony fishes also have a swim- ming bladder, connected with the pharynx (see Fig. 78), which is apparently used partly for breathing (the blood vessels in the wall of the bladder being exposed to moist air) and partly as a means of raising or lowering the body in the water expanded into tail fin or fins. The appendages are normally two pairs, pectoral and pelvic fins (see section 225) ; and there is usually also one fin along the back (dorsal) and one back of the anus on the ventral side; this is usually called the anal or ven- tral fin. ]Most fishes have an exoskeleton consisting of scales or spines, growing out of the skin. The bony fishes have a true jaw, and most species have teeth. The mouth is the only organ among fishes with which food or prey can be grasped, although many of them can fight viciously with their tails, their fins, and various outgrowths of the 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 Gruenberg, Benjamin C. (Benjamin Charles), 1875-1965. Boston, New York [etc. ] Ginn and Company
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Keywords: ., bookcentury1900, bookdecade1920, bookpublishe, booksubjectbiology
