The single most major aspect of shell variation within the genus is the color patterning. In general, many arboreal snails are brightly colored, obvious examples being the bulimulid genera "Drymaeus" and "Liguus", the cepolid "Polymita", and the camaenid "Papuina". However, "Polymita", "Liguus" and "Amphidromus" are particularly noted for their color variations. The basic ground color of "Amphidromus" appears to be yellow, and this color is usually (except for "Amphidromus entobaptus") confined to the surface layers of the shell, since worn specimens appear to be nearly devoid of color. In some species the background color is whitish, and a few have dark background colors. The apical whorls are pale, purple, brown, or black, and this sometimes varies within a population (as in "A. quadrasi"). A few species, for example "A. schomburgki", have a deciduous green periostracum.