Continuous zonal patterns can take the form of whitish subsutural bands ("A. similis"), heavy subperipheral pigmentation ("A. perversus" var. "infraviridis"), subsutural color lines ("A. columellaris"), broad spiral color bands ("A. metabletus", "A. webbi"), or narrow spiral bands ("A. laevus"). Interrupted zonation can consist of the interruption of bands into spots in ("A. maculatus"); highly irregular splitting of zones ("A. perversus" vars. "sultanus" and "interruptus"); formation of oblique radial streaks which run parallel to (in "A. inversus") or cross (in "A. latestrigatus") the incremental growth lines; or almost every conceivable combination and variation of these factors. Often the pattern will change radically from the apex to the body whorl (in "A. quadrasi" vars.). The aperture, parietal callus, columella, lip, and umbilical region are variously marked with pink, brown, purple, white, or black. Haniel (1921) includes several color plates which clearly demonstrate the extent of color variation within two species of the "Syndromus" type. "A. perversus" and "A. maculiferus" of the subgenus "Amphidromus" are equally variable, whereas species such as "A. inversus" and "A. similis" are almost uniform in coloration.