The cavity occupied by the stomach is, you recall, the perivisceral coelom and is lined by peritoneum. The ciliated peritoneum covers every surface in the perivisceral coelom, including the surrounding body wall. The gonads are numerous blind, peritoneal pouches that surround each bursa which release gametes into the bursae. The gametes then move into the sea where fertilization occurs. In these species sperm enter the bursa and fertilization occurs there.
Embryos develop in the bursae and develop into tiny brittle stars before they are released.
Ripe gonads may be seen bulging into the walls of the bursae. It is not practical to study the water vascular, hemal, or nervous systems of Ophioderma . Watch a brittle star as it uses its arms to lasso a shrimp and stuff it into its mouth. It uses two arms as oars and with them rows across the substratum. Another arm extends ahead to sense environmental conditions in the path and two others trail behind.