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

by Charles Darwin

[Plate XX., figure 2 b.]

[Plate XX., figure 3 a.]

[Plate XX., figure 3 b.]

[Plate XX., figure 4 a.]