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A. E. Verrill, J. W. Dawson, and E. Desor named 23 species of North American east coast ectoprocts and entoprocts prior to 1902. Chiefly from lack of illustration, the majority of these have been misunderstood in the literature. We have found material leading to a better understanding of 15 of these species in collections of the Peabody Museum of Natural History, Yale University, the U.S. National Museum, and the American Museum of Natural History. The following ectoproct species are described (original names): Amathia goodei Verrill, Bugula cucullata Verrill, Bugula decorata Verrill, Bugula flexilis Verrill, Bugula (Caulibugula) armata Verrill, Bugulella fragilis Verrill, Cellularia turrita Desor, Discopora nitida Verrill, Escharina porosa Verrill, Gemellaria willisii Dawson, Hippoporina verrilli Maturo and Schopf, Hippothoa expansa Dawson, Lepralia americana Verrill, Lepralia plana Dawson, Porellina stellata Verrill. One entoproct, Barentsia timida Verrill, is described. The coefficient of variation was determined for standard dimensional features. Data collected support Cheetham's statistical verification that the most useful dimensional features for taxonomic purposes are ovicell length and width, zooid length, and primary orifice length and width. Length of adventitous avicularia and zooid width are the most variable of the traits measured, particularly in encrusting forms which also have extensive secondary calcification.