Question

Which among the following does not have placoid scales?

• A. Rays
• B. Silver fish
• C. Skates
• D. Sharks

Answer 1

The correct option is B Silver fish

All the cartilaginous fishes like rays, skates and sharks have placoid scales.

Placoid scales are tooth-like, being made of dentine with a pointed backward projection of enamel, all of which sits on top of a rectangular basal plate that rests on the dermis. Whereas silver fish is a wingless insect which do not possess scales on the dermis.

Therefore, the correct answer is option B.