31. Pseudofeces accumulate with, and look much like, the actual feces in the bottom of the mantle cavity . 32. The anus opens on the ventral / underside of the animal, roughly in the middle of the mantle cavity . 33. The female extends her ovipositor into the mantle cavity of the mussel and deposits her eggs between the gill filaments. 34. In some brachiopods groups of chaetae help to channel the flow of water into and out of the mantle cavity . 35. In aquatic gastropods, the nephridium is drained by a ureter that opens near the rear of the mantle cavity . 36. The ventral surface is bordered with the mantle and moving towards the center of the chiton is the mantle cavity . 37. All nemerteans move slowly, using their external cilia to glide on surfaces on a trail of mantle cavity of molluscs. 38. The female extends her long ovipositor into the mantle cavity of the mussel and deposits her eggs between the gill filaments. 39. During mating, this arm is detached, and kept by the female in her mantle cavity until used for fertilisation. 40. Sperm from these is passed along the extensible penis into the mantle cavity of an adjoining individual where fertilisation takes place.
