Nematodes have no circulatory system and a pseudocoelom while annelids have a closed circulatory system and a true coelom. Nematodes lack the obvious segmentation of annelids and have longitudinal muscles while annelids have circular muscles. This difference in muscular structure leads to differences in the way that locomotion occurs in the two groups.
Work Step by Step
Review the relevant information on annelids and nematodes in Concepts 33.3 and 33.4, making a list of contrasts by first listing aspects of body structure and then adding a note on on each aspect for each of the two named groups. Use that list for writing your answer.