The present status of the taxonomy of the Testacea is unsatisfactory. A considerable proportion of the species forming the Testacean community of Sphagnum swards are poorly described. Thus the identification of many species is rather difficult. This investigation gives the systematic basis to a following ecological paper, whose subject will be the cluster analysis of testate associations in Sphagnum (MEISTERFELD 1979). A new species (Euglypha penardi) is described. The descriptions of remarkable species, most of them with problematic taxonomy, are illustrated by SEM images. These are: Cyclopyxis arcelloides, Difflugia bacillifera, D. nebeloides, D. globulosa, Nebela tenella, N. lageniformis, Awerintzewia cyclostoma, Euglypha penardi n. sp. and Trinema lineare. With exception of T. lineare this is the first information on the ultrastructure of the shells. The morphological variation of Cyclopyxis arcelloides, Heleopera rosea and H. petricola amethystia was studied biometrically.