ABSTRACT
The cirri differ considerably in the two species the same way as in the two species of Chamaesipho. In the structure of the second pair of cirri, and in the tendency of the basal margin of the parietes to form bay-like indentations, Octomeris angulosa shows some special affinity to Chamaesipho scutelliformis. Under Pachylasma, stated that that genus was closely related to Octomeris; and have alluded to the close affinity of the latter to the division of the genus Chthamalus, which has crenated radii. The radii are narrow, and are distinctly crenated on both sides of the sutures with the teeth neatly interlocking; but these teeth can hardly be distinguished in the large, corroded specimens of Octomeris angulosa. The crenated structure of the radii is identical with that described under Chthamalus dentatus and Hembeli; if, indeed, we were to add carino-lateral compartments to the shells of these two species, they would belong to Octomeris.
