We present the results of the first attempt of statistical research devoted to the association between X-ray Plasma Ejections (XPEs) and prominences. For this aim, we compared contents of a catalogue of XPEs, observed by the Soft X-ray Telescope onboard Yohkoh, to H$\alpha$ reports from the Solar-Geophysical Data. We found that only less than one third of XPEs shows a low-temperature counterpart. A modest connection between hot and cool plasma motions in the corona is also supported by by a frequent discrepancy between morphology and kinematics of simultaneously occurring XPEs and prominences. We explain the poor correlation (20-30 %) between XPEs and prominences and high correlations (~70%) between these phenomena and CMEs as a proof of existence of two separate subclasses of CMEs.