Shell small, a full-grown specimen containing eggs being a quarter of an inch in greatest diameter. The shell is conical and almost flat, becoming elongate when crowded. The opercular opening is oval in shape and large in proportion to the shell. The junction of the cover-plates forms a cross which is characteristic of the species.
Pale grey where the shell is eroded, buff in a narrow basal band where the cuticle remains. White in the interior.
Unalaska, southern coast of Alaska, coasts of British Columbia, Washington, Oregon, and California. High in the intertidal zone, often in hollows in the rock or on piles.
Members of this species grow higher in the intertidal zone than any other barnacles. They are therefore exposed to drying for many hours per day. In certain areas fully 90 per cent are sometimes found to be parasitized by the isopod, Homioniscus balani(Spence Bate), which is usually fatal to the host.