The labial tentacles or palps of Anodonta (n, o in fig.
The labial palps are direct continuations of the lips.
- One row of branchial filaments is directed dorsally, the other ventrally; the mantle has a long posteroventral suture and a single posterior aperture; the labial palps of each side are fused together; shell elongate; hinge without teeth; periostracum thick.
The maxillary palps have usually three, the labial either two or four segments.
The palps, both maxillary and labial, have two segments.