You can "vent" this soft, ductless organ that fights infection with parasite detection
[DOC] [TLE] ZOO 211 Study Guide (2012-13 Reinking) - Instructor Reinking at ... [PAR] Jun 30, 2013 ... Online study guide for Zoology 211 with Reinking including What type of body 
plan and organs could you expect in Phylum Rotifera?