I will give one other instance with fowls and pigeons of weakness and strength in the transmission of the same character to their crossed offspring. The Silk fowl breeds true, and there is reason to believe is a very ancient race; but when I reared a large number of mongrels from a Silk hen by a Spanish cock, not one exhibited even a trace of the so-called silkiness. Mr. Hewitt also asserts that in no instance are the silky feathers transmitted by this breed when crossed with any other variety. But three birds out of many raised by Mr. Orton from a cross between a silk cock and a bantam hen had silky feathers. (14/13. 'Physiology of Breeding' page 22; Mr. Hewitt in 'The Poultry Book' by Tegetmeier 1866 page 224.) So that it is certain that this breed very seldom has the power of transmitting its peculiar plumage to its crossed progeny. On the other hand, there is a silk sub-variety of the fantail pigeon, which has its feathers in nearly the same state as in the Silk fowl: now we have already seen that fantails, when crossed, possess singularly weak power in transmitting their general qualities; but the silk sub-variety when crossed with any other small-sized race invariably transmits its silky feathers! (14/14. Boitard and Corbie 'Les Pigeons' 1824 page 226.) The well-known horticulturist, Mr. Paul, informs me that he fertilised the Black Prince hollyhock with pollen of the White Globe and the Lemonade and Black Prince hollyhocks reciprocally; but not one seedling from these three crosses inherited the black colour of the Black Prince. So, again, Mr. Laxton, who has had such great experience in crossing peas, writes to me that "whenever a cross has been effected between a white-blossomed and a purple- blossomed pea, or between a white-seeded and a purple-spotted, brown or maple- seeded pea, the offspring seems to lose nearly all the characteristics of the white-flowered and white-seeded varieties; and this result follows whether these varieties have been used as the pollen-bearing or seed-producing parents." The law of prepotency comes into action when species are crossed, as with races and individuals. Gartner has unequivocally shown (14/15. 'Bastarderzeugung' s. 256, 290, etc. Naudin 'Nouvelles Archives du Museum' tome 1 page 149 gives a striking instance of prepotency in Datura stramonium when crossed with two other species.) that this is the case with plants. To give one instance: when Nicotiana paniculata and vincaeflora are crossed, the character of N. paniculata is almost completely lost in the hybrid; but if N. quadrivalvis be crossed with N. vincaeflora, this latter species, which was before so prepotent, now in its turn almost disappears under the power of N. quadrivalvis. It is remarkable that the prepotency of one species over another in transmission is quite independent, as shown by Gartner, of the greater or less facility with which the one fertilises the other.