H I-deficient spiral galaxies in the Coma cluster and Abell 1367.

The H I content of 11 spiral galaxies in two rather different clusters, Abell 1367 and 1656 (Coma), is compared with that of nearby 'field' spirals on the basis of 21-cm observations. The comparison is performed in terms of the distance-independent logarithmic ratio of hydrogen mass to photographic luminosity. It is found that this ratio lies below the mean value for the corresponding Hubble type for all but one of the cluster galaxies and that eight of the cluster galaxies, including five detections, appear to have lower values than any of the 'field' spirals. The relative H I deficiency in the spiral galaxies of the two clusters is taken as excellent evidence for the operation of an efficient gas-stripping mechanism. The nature of this mechanism is considered.