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Bony Fishes – Class Osteichthyes. Skeleton made of bone Two types of Scales 1) Cycloid scales – smooth 2) Ctenoid scales – tiny spines along their exposed borders. Cycloid scales have a smooth edge. Ctenoid scales have a toothed edge.
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Bony Fishes – Class Osteichthyes • Skeleton made of bone • Two types of Scales • 1) Cycloid scales – smooth • 2) Ctenoid scales – tiny spines along their exposed borders
Cycloid scales have a smooth edge. Ctenoid scales have a toothed edge.
Scales are covered by a thin layer of skin and mucus • Mucus is a protective feature • Operculum or gill cover – flap of bony plates and tissue that protects the gills
Homocercal tail: Upper and lower lobes of the tail are the same size • Fin Rays consist of thin membranes that are supported by bony spines
Jaws are protrusible because they can beprojected outward from the mouth • Teeth attached to the jaw bones and replaced from below
Swim bladder – gas-filled sac just above the stomach and small intestines– allows the fish to adjust itsbuoyancyto keep from sinking or rising