Tribe 2.—Agnatha. No jaws; teeth narrow and pointed; carnivorous.
Fam. 1.—Oleacinidae. Shell oval, elongated, with narrow aperture; neck very long; labial palps prominent. Oleacina (Glandina). Streptostyla.
Fam. 2.—Testacellidae. Shell globular or auriform, external or partly covered by the mantle. Streptaxis. Gibbulina. Aerope. Rhytida. Daudebardia. Testacella. Chlamydophorus. Schizoglossa.
Fam. 3.—Rathouisiidae. No shell, a carinated mantle covering the whole body; male and female apertures distant, the female near the anus. Rathouisia. Atopos.
Tribe 3.—Elasmognatha. Jaw with a well-developed dorsal appendage.
Fam. 1.—Succineidae. Anterior tentacles much reduced; male and female apertures contiguous but distinct; shell thin, spiral, with short spire. Succinea, British. Homalonyx. Hyalimax. Neohyalimax.
Fam. 2.—Janellidae. Limaciform, with internal rounded shell; mantle very small and triangular; pulmonary chamber with tracheae; no anterior tentacles. Janella. Aneitella. Aneitea. Triboniophorus.
Tribe 4.—Ditremata. Male and female apertures distant.
Fam. 1.—Vaginulidae. No shell; limaciform; terrestrial; female aperture on right side in middle of body; anus posterior. Vaginula.
Fam. 2.—Oncidiidae. No shell; limaciform; littoral; female aperture posterior, near anus; a reduced pulmonary cavity with a distinct aperture. Oncidium. Oncidiella, British. Peronia.