Characteristics of chondrichthyes:

(i) They are marine fish with completely cartilaginous endoskeleton and a two-chambered heart.

(ii) They have a streamlined body which is either compressed laterally or flattened dorsoventrally. They have paired or median fins for locomotion and the tail or caudal fin is heteroceral.

(iii) Mouth is ventral in position and respiration occurs via gills.

(iv) Skin is tough and covered with minute placoid scales.

Examples: Scoliodon and Torpedo.