The peristomial disc, which may have ringed ridges or undulations, encloses rows of cilia. These undulations give the hollows and peaks of altitude. This alluvial flatland has a slight westerly-southwesterly slope obscured by gentle undulations. The sound vibrations were recorded as undulations or other irregularities in the traced line. The impacts were well suppressed and the car veritably floated over the undulations and potholes. Larger species use muscular waves to crawl, and some aquatic species swim by dorso-ventral undulations. They have long bodies and swim using undulations of their elongated anal fin. Locomotion in the grey triggerfish is by means of undulations of the dorsal fins. Further classification can be made depending on the smoothness and undulations of the solid surfaces. To the north the land is flat with gentle undulations. This asymmetry in muscle composition causes body undulations that occur in Stage 3. The town is mostly flat, with some slight street undulations. The greens are medium in size and fast in speed with large undulations. The leech moves by producing dorsoventral undulations. It takes the form of three undulations blending into the landscape.