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"Dermal dentricles of <em>Centrophorus</em>."&mdash;Finley, 1917

Dermal dentricles of Centrophorus

"Dermal dentricles of Centrophorus."—Finley, 1917

These placoid scales are found in cartilaginous fishes. They are also called dermal denticles. These scales do not grow in size, more are simply added as the fish grows larger.

Placoid Scales of a Shark

These placoid scales are found in cartilaginous fishes. They are also called dermal denticles. These…

"A block out of the skin. a, dead part and d live part of the epidermis; e, sweat glands; n, nerve endings." &mdash;Davison, 1910

Section of skin

"A block out of the skin. a, dead part and d live part of the epidermis; e, sweat glands; n, nerve endings."…

"Dermal spines of a male Thornback, Raia clavata." &mdash; Encyclopedia Britannica, 1893

Spines

"Dermal spines of a male Thornback, Raia clavata." — Encyclopedia Britannica, 1893