Internal motions in three dwarf irregular galaxies.

Internal motions in the three extreme dwarf galaxies VV 499, 558 and 828 - all being the members of nearby groups of galaxies are studied. Each of them is found to rotate. The masses of the galaxies are obtained. All the galaxies under consideration have absolute magnitudes weaker than -14^m, diameters of 0.5 - 2.0 kpc and masses smaller than 10⁸M_sun;. They contain H II regions about 100 pc in diameter and this fact has led to their formal classification as interacting systems. The comparison of integral characteristics of the dwarf galaxies belonging to different groups (M81, M101 and the Local Group) has revealed their significant resemblance.