Psolidiella

Mortensen, 1925

4 species

Like Psolus, with a distinct creeping sole, which however is not bordered by a crest; the body, except for the creeping sole, symmetrical, without feet. Mesentery of the last intestinal loop attached to the left ventral interradius. In the body skin, simple plates or branched rods. (Panning, 1949)

Body Psolus-like in shape, with ventral sole, but sole not sharply delimited from rest of the body by a sharp edge. Dorsal surface with numerous tube feet which show no serial arrangement. Calcareous deposits small plates up to 0.15 mm in length. (Pawson, 1970)

The shape is similar to Psolus, with a more distinct creeping sole which, however, is not separated by means of a ridge from the back. The mouth is terminal positioned; the anus faces obliquely upwards on a short tube. The feet, ventral in the region of the creeping sole, are confined to the radii, on both ends of the body, with the exception of the creeping sole and on the back, they are equally distributed in radii and interradii. There are 10 tentacles, the two ventral ones smaller. The calcareous ring is strong and without forked tail. The calcareous deposits of the skin: to the surface they are quite sparse, X variety small structures (retrogressive cups) deeper in the skin they are large, thick, smooth, perforated plates, in the creeping sole, they are closely positioned, in the dorsal area they are sparser. (Panning, 1971)

* Mortensen noted that the last intestinal loop runs to the left ventral interradius, a characteristic of the Cucumariidae. It runs to the right ventral interradius in the Psolidae. (Panning, 1971)