2. There may be what is known to practical students of evolution as the _false hybridism of Millardet_, or in other words, fertilisation with--from unknown causes--transmission of none or of only some of the characters of one pure parent. The applicability of this hypothesis to the colours and shapes of peas is perhaps remote, but we may notice that it is one possible account of those rare cases where two pure forms give a _mixed_ result in the first generation, even assuming the gametes of each pure parent to be truly monomorphic as regards the character they bear. The applicability of this suggestion can of course be tested by study of the subsequent generations, self-fertilised or fertilised by similar forms produced in the same way. In the case of a _genuine_ false-hybrid the lost characters will not reappear in the posterity. 3. The result may not be a case of transmission at all as it is at present conceived, but of the creation on crossing of something _new_. Our _AB_’s may have one or more characters _peculiar to themselves_. We may in fact have made a distinct “mule” or heterozygote form. Where this is the case, there are several subordinate possibilities we need not at present pursue. 4. There may be definite _variation_ (distinct from that proper to the “mule”) consequent on causes we cannot yet surmise (see pp. 125 and 128). The above possibilities are I believe at the present time the only ones that need to be considered in connexion with these exceptional cases[75]. They are all of them capable of experimental test and in certain instances we are beginning to expect the conclusion. [75] I have not here considered the case in which male and female elements of a pure variety are not homologous and the variety is a _permanent_ monomorphic “mule.” Such a phenomenon, when present, will prove itself in reciprocal crossing. I know no such case in peas for certain. _The “mule” or heterozygote._ There can be little doubt that in many cases it is to the third category that the phenomena belong. An indication of the applicability of this reasoning will generally be found in the fact that in such “mule” forms the colour or the shape of the seeds will be recognizably peculiar and proper to the specimens themselves, as distinct from their parents, and we may safely anticipate that when those seeds are grown the plants will show some character which is recognizable as novel. The _proof_ that the reasoning may apply can as yet only be got by finding that the forms in question cannot breed true even after successive selections, but constantly break up into the same series of forms[76].