question_answer

Scales in Chondrichthyes are:

A)  placoid                               

B)         canoid                

C)  cycloid                

D)         sysamoid

Correct Answer: A

Solution :

Placoid scales are found in cartilaginous fishes (Chondnchthyes). Each placoid scale contains a spine which directs towards back. It arises from a basal plate which is embedded in skin dermis. A pulp cavity occurs inside the spine which opens through basal plate.