G. J. Adler

“ A. The adjectives in er, is, e are but few in number. The nominative masculine has sometimes is instead of er. So decline alacer or alacris, cheerful; celeber or celebris, famous; celer or celeris, swift; salūber or salūbris, wholesome.
Adjectives of One Termination. B. Adjectives of one termination do not differ essentially from other words of the third declension, except that they may have either e or i in the ablative. ”