2. Agnathans Most primitive fish Jawless, no paired appendages
Eel-shaped body
Cartilagionous skeletons
Hagfish and Lamprey

3. Chondrichthyes Sharks, Skates, Rays, Ratfishes
Jaws and Cartilaginous skeleton
Gill Slits, Spiracle and Claspers
No Swim Bladder
Placoid Scales

4. Placoid scales
Superficially look like the scales of bony fish, but are actually modified teeth!

5. Osteichthyes Bony Fish Fin Spines and Rays Swim Bladder Gill Cover
Otolith
Most Diverse

6. Types of Scales Sharks/Rays Sturgeons/Gars Salmon/Carp Perch
(Most Bony fish)