This paper is a continuation of a paper by \textit{M. W. Chan} and \textit{K. P. Shum} [Semigroup Forum 46, 7-15 (1993; Zbl 0776.06012)] on negatively ordered implicative semigroups. Here the emphasis is on the connection between implicative morphisms and semigroup morphisms. In particular it is shown that every implicative morphism is an isotone semigroup morphism. The authors also correct a false proof given in the above paper.