Placoid scales are found in
Answers
Explanation:
Sharks have placoid scales, which are boney and spiny projection with an enamel like covering . They are found on such fishes as gars and bowfin are similar to placoid scales but are covered with a peculiar enamel like substance called ganoin
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Answer:
Cartilageneous fishes or chondrycthes,
Explanation:
Placoid scales are hard and teeth like . They are derived from the dermis of the skin. These are found in chondrycthes. The fishes has been grouped into two types , namely the bony fishes or ostychthes like Labeo , Rohu etc and the chondrycthes like Shark. Placoid scales grow till the organism matures and they stop growing after the organism attains maturity. These are also known as dermal dentines due to their teeth like structure and dermal origin.