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Collections of Balanus amphitrite Darwin have been made along the Guinea Coast, and varieties denticulata, venustus and stutsburi have been identified. Of these only var. stutsburi appears in Lagos Harbour, but these individuals have shown so much variation of their morphological characters that they have led to a more detailed study to try to ascertain the inter-relationships of the various var. stutsburi populations found along the coast, and to see whether any of these could be entering the Harbour.

Certain characters, mainly referring to proportional measurements of the tergum and scutum and the numbers of segments on the cirri, have been chosen for closer analysis. The more variable characters shown by var. stutsburi have been selected for this, in the hope of (a) finding more accurate methods for describing the variable characters of a variety and giving their limits of variation, and (b) to find possible elines in the characteristic features as shown by the var. stutsburi populations on the Guinea Coast.

As a result of this analysis the relationships between the “centre” of the population in Kuramo, near Lagos Harbour, and the populations in the surrounding lagoons is clarified, and the populations at Irewe and Port Harcourt are found to show slight (but definable) trends differing from those in the Lagos area.

B. amphitrite var. pallidus, recorded by Darwin from West Africa, has not been identified amongst the collections, but the possibility that it may be synonomous with var. stutsburi is discussed. The necessity for a re-description of the type specimens is emphasized, and more accurate methods for the description of new species and varieties is advocated.