ON THE ABORIGINAL PARENT-STOCK OF THE SEVERAL DOMESTIC RACES. HABITS OF LIFE. WILD RACES OF THE ROCK-PIGEON. DOVECOTE-PIGEONS. PROOFS OF THE DESCENT OF THE SEVERAL RACES FROM COLUMBA LIVIA. FERTILITY OF THE RACES WHEN CROSSED. REVERSION TO THE PLUMAGE OF THE WILD ROCK-PIGEON. CIRCUMSTANCES FAVOURABLE TO THE FORMATION OF THE RACES. ANTIQUITY AND HISTORY OF THE PRINCIPAL RACES. MANNER OF THEIR FORMATION. SELECTION. UNCONSCIOUS SELECTION. CARE TAKEN BY FANCIERS IN SELECTING THEIR BIRDS. SLIGHTLY DIFFERENT STRAINS GRADUALLY CHANGE INTO WELL-MARKED BREEDS. EXTINCTION OF INTERMEDIATE FORMS. CERTAIN BREEDS REMAIN PERMANENT, WHILST OTHERS CHANGE. SUMMARY. The differences described in the last chapter between the eleven chief domestic races and between individual birds of the same race, would be of little significance, if they had not all descended from a single wild stock. The question of their origin is therefore of fundamental importance, and must be discussed at considerable length. No one will think this superfluous who considers the great amount of difference between the races, who knows how ancient many of them are, and how truly they breed at the present day. Fanciers almost unanimously believe that the different races are descended from several wild stocks, whereas most naturalists believe that all are descended from the Columba livia or rock-pigeon. Temminck (6/1. Temminck 'Hist. Nat. Gen. des Pigeons' etc. tome 1 page 191.) has well observed, and Mr. Gould has made the same remark to me, that the aboriginal parent must have been a species which roosted and built its nest on rocks; and I may add that it must have been a social bird. For all the domestic races are highly social, and none are known to build or habitually to roost on trees. The awkward manner in which some pigeons, kept by me in a summer-house near an old walnut-tree, occasionally alighted on the barer branches, was evident. (6/2. I have heard through Sir C. Lyell from Miss Buckley, that some half-bred Carriers kept during many years near London regularly settled by day on some adjoining trees, and, after being disturbed in their loft by their young being taken, roosted on them at night.) Nevertheless, Mr. R. Scot Skirving informs me that he often saw crowds of pigeons in Upper Egypt settling on low trees, but not on palms, in preference to alighting on the mud hovels of the natives. In India Mr. Blyth (6/3. 'Annals and Mag. of Nat. Hist.' 2nd series volume 20 1857 page 509; and in a late volume of the 'Journal of the Asiatic Society.') has been assured that the wild C. livia, var. intermedia, sometimes roosts in trees. I may here give a curious instance of compulsion leading to changed habits: the banks of the Nile above lat. 28 deg 30' are perpendicular for a long distance, so that when the river is full the pigeons cannot alight on the shore to drink, and Mr. Skirving repeatedly saw whole flocks settle on the water, and drink whilst they floated down the stream.