Descriptions of Four New Species of the Balanus Amphitrite-Complex (Cirripedia, Thoracica)

Two new species of barnacles from the western Atlantic and two new species from the eastern Pacific are described. One species, which has a multidenticulate labrum, shows the closest affinity to Balanus amphitrite amphitrite Darwin. The other three species are more closely related to another group of the B. amphitrite-complex, as these species have more than a single row of tubes in the parietes and complex cirral setae. Heretofore, specialized cirral setae have been considered one of the characters that differentiate the Balanidae, except Elminius, from the Chthamalidae and Tetraclitidae. Another character, a vesicular sheath, found in all four species, has not been known previously in balanids.