Revision of the Cheilostomatida (Bryozoa) collected during the HMS 'Challenger' Expedition (1872-1876) in the central North Atlantic

Of the 21 species recorded from the greater Azores region during the HMS 'Challenger' Expedition, 12 were newly introduced during the late 19th century. The respective types of these species are fixed, and eight species are redescribed based on scanning electron microscope analysis (Notoplites bilobus, Raxifabia minuta, Hemicyclopora canalifera, Smittoidea oratavensis comb. nov., Buskea ovalis comb. nov., Buskea fayalensis comb. nov., Celleporina ansata comb. nov. and Reteporella atlantica comb. nov.). Another four species are merely dealt with shortly either because the material is insufficiently preserved for a thorough revision (Columnella gracilis, Carbasea pedunculata), or because the species have recently been revised already (Notoplites clausus, Microporella hastigera). Moreover, two Azorean species that were introduced by later workers are synonymized with 'Challenger' species: S. oratavensis is considered a senior synonym of Smittia ensifera, and Lekythopora laciniosa is synonymized with C. ansata.