The sporidia are usually four or eight, or some multiple of that number, in each ascus, rarely four, most commonly eight. At a fixed time the protoplasm, which at first filled the asci, disappears or is absorbed in a mucilaginous matter, which occupies its place, in the midst of which is a small nucleus, which is the rudiment of the first spore; other spores are formed consecutively, and then the substance separates into as many sections as there are sporidia. From this period each sporidium seems to have a separate existence. All have a nucleus, which is scarcely visible, often slightly granular, but which is quite distinct from the oleaginous sporidioles so frequent amongst the Discomycetes, and which are sometimes called by the same name. The sporidia are at first a little smaller than when mature, and are surrounded by mucilage. After this period the sporidia lose their nebulous granulations, whilst still preserving their nucleus; their outlines are distinct, and, amongst the true _Ascobolei_, commence acquiring a rosy colour, the first intimation of maturity. This colour manifests itself rapidly, accumulating exclusively upon the epispore, which becomes of a deep rose, then violet, and finally violet blue, so deep as sometimes to appear quite black. There are some modifications in this coloration, since, in some species, it passes from a vinous red to grey, then to black, or from rose-violet to brown. The epispore acquires a waxy consistence by this pigmentation, so that it may be detached in granules. It is to this particular consistency of the epispore that the cracks so frequent in the coloured sporidia of _Ascobolus_ are due, through contraction of the epispore. As they approach maturity, the sporidia accumulate towards the apex of the asci, and finally escape in the manner already indicated. In all essential particulars there is a great similarity in the structure of the other Discomycetes, especially in their reproductive system. In most of them coloured sporidia are rare. In some the receptacle is pileate, clavate, or inflated, whilst in _Stictis_ it is very much reduced, and in the lowest form of all, _Ascomyces_, it is entirely absent. In the _Phacidiacei_, the structure is very similar to that of the _Elvellacei_, whilst the _Hysteriacei_, with greater affinities with the latter, still tend towards the _Pyrenomycetes_ by the more horny nature of the receptacle, and the greater tendency of the hymenium to remain closed, at least when dry. In some species of _Hysterium_, the sporidia are remarkably fine. M. Duby[AA] has subjected this group to examination, and M. Tulasne partly so.[AB]