WEBviz., Sacculina gonoplaxae GuérinGanivet Sacculina, atlantica Boschma ,and. Sacculina zariquieyi Boschma. In a previous paper (Boschma com , 1947) I mented upon th difficultiee fos rdefinin thgespecifi characterc s of S. gono-plaxae, S. atlantica, and S. zariquieyi, thre speciee wits hinconspicuou difs