Snout very long, bilobed; foot short.
The foot is always simple, with its flat crawling surface extending from end to end, but in the embryo Limnaea it shows a bilobed character, which leads on to the condition characteristic of Pteropoda.
The young foot shows a bilobed form.
The mass of the arch-enteron or invaginated endodermal sac has taken on a bilobed form, and its cells are swollen (gs and tge).
Crown of the last lower molar commonly bilobed.