Paper on Earthworm Smooth Muscle Krajniak, K.G., R. W. Klohr. 1999. The effects of FMRFamide, serotonin, and acetylcholine on the isolated crop-gizzard of the earthworm, Lumbricus terrestris. Comp Biochem Physiol Part A 123: 409-415. If you try to access this paper from off campus you will need to supply your library user name and ID number.