This is a supplement to the previous papers [5] and [6] of the author in which the structure of strictly regular semigroups has been clarified. By using the results of [5], [6], at first we shall show how to construct every inversive semigroup. Secondly in the latter half of the paper we shall investigate the relations between quasi-direct products and spined products, and give another proof for the structure theorem for strictly inversive semigroups which has been established in the previous paper [4]. Any notation and terminology should be referred to [5], [6], unless otherwise stated.