Following are the main characteristics of Chondrichthyes fishes:
1. The members of this class are marine
2. Their endoskeleton is cartilaginous.
3. The external skeleton is made of placoid scales.
4. 5-7 pairs of gill slits are found in them.
5. Operculum is absent on gill cracks.
6. J-shaped stomach is found in them and spiral valve is found in their intestine.
7. Clasper is found as sexual organ in male animals.
8. Heat receptors called ampulla of Lorenzini are found on the dorsal side of the head of this group of fish.
9. Two chambers are found in the heart, one atrium and one ventricle. Apart from these, venules and cone arteriosus are found in the heart.
10. They have internal fertilisation and many of them are viviparous. Examples Scoltodon (Dog fish), Pristis (Saw fish), Carcharodon (Great white shark). Trygon (Sting ray).