Compact extragalactic nonthermal sources.

Results of photometry, polarimetry, spectroscopy, and direct photography at visual wavelengths of four additional objects of the BL Lacertae type are reported together with infrared observations to 10 microns for one of them (OJ 287). The data indicate that these objects are compact sources of nonthermal continuum radiation. They are likely to be extragalactic, and their possible relationship to QSOs is discussed.