Hybrid Oochromy, with a Note on Xenia

Abstract

IN a note on “Telegony, Xenia and Hybrid Oology,”¹ which appeared in Natural Science (vol. xiv. p. 394, 1899), I introduced the last-mentioned term to denote a singular phenomenon said to have been observed in birds, viz., that when a hen is fertilised by a cock of another kind the resulting egg is contained in a shell tinted, more or less, like those laid by the cock's own breed. At the time, I must confess, I was rather inclined to doubt if it did really occur, or if it were not a simple reversion, or a mistake, when my attention was drawn still closer to the subject by a friend who had kindly offered to assist in obtaining, if it were possible, additional proofs of telegony by first crossing a canary hen with a greenfinch cock and then returning her to her own breed. This was done, and resulted in three eggs being laid to the greenfinch. Their shells were all tinted more like the eggshells of a greenfinch than those of a canary. Two of these eggs were afterwards found to be infertile. This showed that the alteration in the tint of the eggshell had nothing to do with the nature of the fertilising spermatozoon. But the occurrence of hybrid oochromy could not be said to have been proved, for there is very little difference in the tinting of the eggshells of a canary and greenfinch, and I do not know whether the canary was purely bred or not.