CARTILAGINOUS FISHES | BONY FISHES |
1) Their endoskeleton is primarily made of cartilage. | 1) Their endoskeleton is entirely made of bone. |
2) Their exoskeleton is made of placoids. | 2) Their exoskeleton is made up of cycloids or thin bony plates. |
3) The position of their tail is heterocercal. | 3) Their tail fin is homocercal. |
4) They have 5 gills that are overly exposed (no operculum). | 4) They have an operculum on either side of their gills. |
5) In them the fertilization is through internal mechanisms. | 5) They fertilize their eggs externally. |
6) Eg- dog fish, electric ray torpedo and sharks. | 6) Eg- fying fish, globe fish and sea horses. |