A catalogue is presented containing spectral classes, on the Case infrared system, for 723 red variable stars in a belt 12 in width, centered on the galactic equator, and extending from longitude 33& through zero to 201 . All known variables to the limiting photographic magnitude of 15.0 at maximum were selected. The statistical discussion is based on 541 M-type variables for which sufficiently reliable data are available The spectral distribution is shown in the form of histograms for the Mira, long-period, semi regular, and irregular types of variability. The first two groups show a spectral range between M2 and M10, while the two latter groups are strongly concentrated at M6 and M6.5, with none later than M7. Only 20 per cent of the M-type variables are earlier than MS Frequency distributions in galactic longitude seem to indicate that the Mira and long-period types tend to concentrate along the local spiral arm, while the semiregular and irregular types form a disk distribution. However, these conclusions must be regarded as tentative. An examination of the period-spectrum relation does not show significant differences at different galactic latitudes However, the number of M variables in each subgroup is small. The galactic zone includes 110 carbon stars which are variable and 12 S-type stars The period-frequency distribution of the carbon stars shows that about one-third of them have periods betwen 360 and 440 days.