Morphological investigations of some British Carboniferous bryozoan taxa has allowed aspects of their palaeobiology and systematics to be revised. Forty-one taxa, representing seventeen genera of nine families in the extinct Palaeozoic orders Cryptostomata, Fenestrate, Trepostomata and Cystoporata, are redescribed. Lectotypes have been established wherever necessary. Three new species are described and holotypes have been selected for these. Ordinal, familial and generic assignments have been made and diagnoses emended. Significant aspects of ordinal, familial and generic morphological characters have been discussed. Skeletal ultrastructures have been analysed in most forms studied and the function of a number of morphological characters has been reviewed. Evidence of the double walled concept of growth in the four extinct stenolaemate order have been reviewed. Extensive quantitative studies have allowed precise assessment of taxa, and the accurate definition and quantification of some unusual aspects of skeletal morphology, notably in Rhabdomeson rhombifera (Phillips). Combined with the quantitative studies there are extensive photographs and illustrations of the new and redescribed taxa. Geological ranges have been established for all taxa described
