Note 71 — 1. Family BALANIDÆ, (or Sessile Cirripedes). (continued 3)
Reading edition
In the case of one young shell, I found that the previously-formed circumferential slip must have split, long before it had assumed its proper and ordinary width; for the last-formed slip of basal membrane was of extreme narrowness, and would have to be considerably added to in width, whilst the new and narrow circumferential slip was likewise being added to in width. This slip of basal membrane, though so extremely narrow, had its own cement-ducts and glands.