Assignment 4: Class Petromyzontida 10. List three features of the larval lamprey (ammocoete) shared with lancelets viewed in assignment 1. 11. List three features of the iarval lamprey (ammocoete) that are NOT shared with lancelets. Assignment 5: Class Chondrichthyes 12. How many fins are present? List them. 13. What is the function of the lateral line system? Where are the receptors located? 14. Why do you suppose the lateral line system has been retained in fishes and some aquatic vertebrates but lost in reptiles, birds, and mammals? 15. What is the function of the spiral valve and the rectal gland? 16. In what way are sharks adapted for a predatory life habit? 17. Briefly describe respiration in fishes. What adaptive mechanism increases efficiency? What is "countercurrent flow" meant as it applies to fish gills? Diagram may help 18. Compare the osmotic problem and mechanism of osmotic regulation in freshwater and marine bony fishes: Again diagrams may help..

1. Assignment 4: Class Petromyzontida 10. List three features of the larval lamprey (ammocoete)
shared with lancelets viewed in assignment 1. 11. List three features of the iarval lamprey
(ammocoete) that are NOT shared with lancelets. Assignment 5: Class Chondrichthyes 12. How
many fins are present? List them. 13. What is the function of the lateral line system? Where are
the receptors located? 14. Why do you suppose the lateral line system has been retained in fishes
and some aquatic vertebrates but lost in reptiles, birds, and mammals? 15. What is the function of
the spiral valve and the rectal gland? 16. In what way are sharks adapted for a predatory life
habit? 17. Briefly describe respiration in fishes. What adaptive mechanism increases efficiency?
What is "countercurrent flow" meant as it applies to fish gills? Diagram may help 18. Compare the
osmotic problem and mechanism of osmotic regulation in freshwater and marine bony fishes:
Again diagrams may help.