1. Chondrichthyes
The Cartilage Fish p

2. Characteristics: - Skeletons of cartilage
- Tooth-like scales (placoid)
- Sharks, skates, rays
- Replaceable teeth
- First to show paired fins
- Swim to maintain buoyancy
(lack swim bladder)

3. External Anatomy Fusiform body Placoid scales Spiracles Lateral line
Detect changes in water pressure and chemistry
Fins:
Pectoral
Pelvic
Dorsal
Caudal
Anal

4. Internal Anatomy Lorenzini pores in nostril Intestinal spiral valve
Slows passage of food for increase absorption

5. Fertilization Internal fertilization Oviparous (egg)
Oviviparous (egg hatches inside body and young born live but without placental attachment)
Viviparous (live birth)
* All three found in species of sharks, skates, and rays

6. Bull Shark

7. Hammerhead Shark

8. Great White Shark

9. Whale Shark

10. Frilled Shark

11. Goblin Shark

12. Megalodon - Prehistoric

13. Giant Stingray

14. Stingray

15. Sawtooth

16. Manta Ray