On the basis of analysis of the inner structure of Stropheodontacea the morphological terminology applied in the Russian literature to this group has been improved. The Russian and English terms have been considered in the context of their synonymy. Some recommendations are given concerning the translation of English terms into Russian and usage of their Russian equivalents. New species of Stropheodontacea Protodouvillina magna Yazikov, sp. n. and Protodouvillina acorrugata Gratsianova, sp. n. are described. New term "vestigial dentickpar plates" is given. Analysis is given to the stratigraphic distribution of the Siberian species of the genus Protodouvillina for the Emsian Givetian interval of the Devonian section, which permits an autonomous zonal scale of the high resolution to be developed. Geographical relations of the Altai-Salair basin to the basins of Siberia, Europe, and North America in the Early and Middle Devonian are evidences by the presence of closely-related species of Protodouvillina in the mentioned regions.
