Across
- 2. protective plate that covers a fish's gills
- 6. membranous organ that develops in female mammals during pregnancy
- 7. vertebrate that has four limbs
- 9. protein that creates the water repellent layer of a cell
- 11. large sheets of thin frilly tissue that take in dissolved oxygen from the water and release carbon dioxide
- 12. aquatic larvae of frogs
- 13. almost completely waterproofed container that keeps the embryo from drying out during development
- 15. fan-shaped array of bones support this type of fin
- 16. paired pectoral and pelvic fins that are round in shape
Down
- 1. flexible skeletal support rod embedded in the animal's back
- 3. system containing series of of shallow canals on the sides of fish that are sensitive to small changes in water movement
- 4. animal that can live both on land and in water
- 5. internal skeleton built of bone or cartilage
- 8. buoyancy organ found in fish that helps them conserve energy
- 10. has a thin, tough membranous sac that encloses the embryo or fetus
- 14. found in the pharynx of fish and some amphibians, supports the gills