Archachatina marginata ICTERICA

Most of the time when someone labels his/her snail as icterica, it is not. It is ovum albino shell. What is the difference? The "true" icterica is an albino form of arch. marginata marginata so yes, the shell is yellow but smaller and more narrow than ovum (just like marginata marginata has) and the columella is white with slightly bluish glint (ovums have their columella anywhere from peach orange to carrot orange).