Across
- 2. a structure that acts like a lid or cover, typically protecting a sensitive body part
- 3. a small elongated marine invertebrate that resembles a fish but lacks jaws and obvious sense organs.
- 6. tiny, tooth-like projections that cover the skin of cartilaginous fish
- 9. common chamber and outlet into which the intestinal, urinary, and genital tracts open
- 13. one of the two upper chambers in the heart that receives blood from the circulatory system.
- 14. a sensory system that helps fish and amphibians detect water flow and pressure changes
- 15. a fin located on the back of some aquatic vertebrates
- 16. a cartilaginous skeletal rod supporting the body in all embryonic and some adult chordate animals.
- 17. muscular chamber that pumps blood out of the heart and into the circulatory system
- 18. a cartilaginous fish with a flattened body shape and enlarged pectoral fins that are fused to its head
- 19. bottom-dwelling, eel-shaped marine creatures that are jawless, primitive fish with a unique evolutionary position
- 20. a group of bony fish with fleshy, paired fins that are attached to the body by a single bone
Down
- 1. a pair of fins on a fish that are located near the front of the fish's body and help it steer, brake, and propel itself
- 4. a marine tunicate that has a body with orifices through which water flows into and out of a central pharynx.
- 5. an organism whose body temperature is primarily regulated by the temperature of its surrounding environment
- 7. jawless fish that are part of the ancient order of vertebrates known as Agnatha
- 8. a gas-filled organ in fish that helps them maintain buoyancy, breathe, produce sound, and possibly sense pressure changes
- 10. the primary appendage that fish use to move through water
- 11. a class of bony fish with fins supported by thin, bony rays
- 12. a flat-bodied, cartilaginous fish in the order Rajiformes