Species Dubiæ.
The Coronula bifida is an Italian tertiary species, so named by Bronn, in his “Italiens Tertiär-Gebilde” (1831), p. 126. It is very possible that this may be identical with C. barbara, but Bronn does not seem to have been aware of the absolute necessity of giving minute details in his descriptions of fossil cirripedes. The chief character of C. bifida is thus given:—“Eine tiefe Furche oder Spalte theilt die Längenrippe von oben herab bis zur Hälfte, welche bei der sonst ähnlichen C. diadema entweder ganz fehlt, oder nur zuweilen kurz angedeutet ist.” Had it been stated that the longitudinal ribs were divided from the middle down to the base, instead of from the top to the middle, the description would have been intelligible to me, though the character thus afforded would not have been of specific value, as this dividing of the ribs occasionally occurs in all four species, and is produced by the formation of new folds to the walls.