Use additional pins to hold the integument open and expose the organs. Continue to lay the skin back until you have uncovered a centimeter or so of the intestine. Use Figure 1 to help you identify the internal organs of the digestive and reproductive systems. Gently press on the crop and gizzard to test their firmness. The gizzard is followed by a long intestine in which both digestion and absorption occur.
Undigested material is voided through the anus .
Note the infolding of the dorsal surface of the intestine. This is called the typhlosol which doubles the surface area for absorption. The cells surrounding the exterior surface of the intestine are called chloragogue cells . Earthworms are hermaphrodites with complex male and female reproductive organs present in each individual, but they cross fertilize. Two earthworms mate by attaching at their clitella and exchanging sperm, and then they separate.