Phylum Annelida, Class Oligochaeta.
Earthworms are the starting point for dissection for beginning students as well as advanced students.
NOTE: Dissection specimens are initially preserved with a formaldehyde solution. Then the solution is removed through a series of water baths before a glycol solution is added to produce a moist, low-fume specimen which can be stored almost indefinitely. All specimens should be used within a year of purchase to ensure the best tissue quality.