Zoology 10th Edition by Stephen Miller,John Harley

Exercise 3

Distinguish between a protonephridium and a metanephridium. Name a group of annelids whose members may have protonephridia. What other phylum have we studied whose members also had protonephridia? Do you think that metanephridia would be more useful for an animal with an open or a closed circulatory system? Explain.