Explain superclass - pisces

The subphylum 'Gnathostomata' is divided into six different classes. Out of the six two classes, Chondrichthyes and Osteichthyes combine together to form a super-class, called Pisces.

Chondrichthyes:

(i) Marine fishes with completely cartilaginous endoskeleton. They are generally large in size.

(ii) Streamlined body is either laterally compressed or spindle-shaped or dorsoventrally flattened and disc shaped.

(iii) Mouth is ventral in position.

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

(v) Heart is two chambered.

(vi) Excrete urea (ureotelic animals).

Example: Scoliodon (dog fish) and Torpedo ( electric ray)

Osteichthyes:

(i) Marine and fresh water fishes with partly or whole bony endoskeleton.

(ii) Body is generally spindle shaped.

(iii) Mouth is usually terminal in position.

(iv) Skin is either naked or covered with cycloid or ctenoid scales.

(v) Heart is two chambered containing one auricle and one ventricle.

(vi) Excrete ammonia (ammonotelic animals).

Example: Labeo (Rohu) and Synchiropus splendidus (mandarin fish)