Note 24 — 1. Family BALANIDÆ, (or Sessile Cirripedes).

In the genus Alcippe, and in Cryptophialus, the whole of the external membranes are moulted, excepting the surface of attachment; but then these Cirripedes live in cavities which they form for themselves, and are thus protected. In Lithotrya the membrane of the peduncle, with its little valves or scales, is moulted, but here, again, this very part is protected by the tubular cavity, which the animal forms and inhabits. Neither of these three genera belong to the Balanidæ, or sessile Cirripedes, which we are now more especially describing.