A Monograph on the Sub-class Cirripedia · Charles Darwin
SECOND SECTION OF THE SUB-FAMILY OF BALANINÆ.
_Dimensions._--The average size of the numerous specimens which I obtained at the Galapagos Islands was about .2 of an inch in diameter, and I found none larger; but Mr. Cuming's specimens from Lord Hood's Island are half an inch in diameter. _Opercular Valves._--These closely resemble those of the former species, with the exception that the carinal end of the growing or under surface of the Tergum is much squarer. _Cirri._--The only difference which I could perceive was, that the rami of the first pair were not quite so unequal in length. _Species Dubiæ._
Text from Project Gutenberg, public domain in the United States.