A Monograph on the Sub-class Cirripedia (Volume 2 of 2) / The Balanidæ, (or Sessile Cirripedes); the Verrucidæ, etc., etc.

by Charles Darwin

[Plate XVIII., figure 4 a.]

[Plate XVIII., figure 4 b.]

[Plate XVIII., figure 5 a.]

[Plate XVIII., figure 5 b.]