Neutral hydrogen in binary and multiple galaxies

We report on H I observations of 28 galaxies selected from the Uppsala General Catalog of Galaxies for belonging to pairs or small groups. The H I distributions are mostly resolved by the Arecibo beam and we give for each object the H I size, total H I flux and mass, redshift and rotation velocity, and spin orientation. We derive total indicative mass in individual galaxies and individual mass-to-light ratios; we also derive a ''nominal pair mass'' for each pair, but this quantity has only statistical validity. We point out a possible tendency for total mass-to-light ratios to be very similar within pairs, already noted by Dickel and Rood [Astron. J. 85, 1003 (1980)]