Earthworms Do Not Have Lungs.
How Does Oxygen Enter an Earthworm’s Body?
While earthworms do not have lungs, like you, they must have oxygen to live.
Instead of lungs, earthworms have a thin permeable skin through which oxygen in air passes through.
The oxygen does not directly pass through the earthworm’s thin outer skin. Instead, the oxygen must first mix with the moist slime on the earthworms skin. It is this mixture that passes through the skin as well as the very thin tissue of capillaries under the skin.
Blood in dorsal vessel moves toward the anterior (head) end. Blood in the ventral vessel moves toward the posterior (rear) end.
Every segment is separated by septae (a vertical wall of tissue). In each segment compartment, except for the first three on the anterior end and the last one on the posterior end, are two nephridia. The ends of these tube structures extend through the outside skin of the earthworm. Waste gases pass from the segment compartment outside the body.