Coloration of Eggs 75 



must not be too hastily assumed that they originate merely 

 in chance blood-marks. Their persistence, and general 

 uniformity of disposition, is sufficient to preclude the idea 

 of chance, while the colour may be as easily washed from 

 many eggs that are habitually spotted e.g. those of some of 

 the accipitres, grouse, thrushes, and so forth ; and even 

 though analysis should prove the colour to be due to blood 

 alone, which I do not think is the case, it would scarcely 

 justify the exclusion of the spots from all association with 

 marks admittedly resulting from various other pigments. 

 Rather, in that case, might they be regarded as pointing to 

 the probable origin of some of those pigments, as rudi- 

 mentary steps in the evolution of coloured eggs, or, as the 

 last remnant of degraded spots, and for various reasons I 

 prefer to look upon them in the former aspect. They seem 

 to bear a close relationship to those spots often seen on the 

 eggs of Whinchats, Stonechats, etc., and why such birds 

 should almost as frequently produce plain as spotted eggs is 

 a subject upon which we possess as yet little or no know- 

 ledge. The eggs of many other birds which are normally 

 spotted are also frequently found without markings 

 Blackbirds, Thrushes, Jackdaws, and Finches, for example ; 

 while eggs of reptiles, from which birds are descended, are 

 always plain. Might we not, therefore, plausibly conclude 

 that all avine eggs were originally white and that colour is a 

 comparative innovation ? On this hypothesis the occasion- 

 ally spotted eggs of such species as Redstarts, Martins, or 

 Chats, might mark the early stages of a permanent advance, 

 and succeeding generations may come to regard an unspotted 

 specimen of any of them as a rarity. The eggs of domestic 

 poultry are not uncommonly more or less spotted, some- 

 times quite as much so, and as regularly, as those of the 

 Turkey, and the spots are not removable by washing. Certain 

 strains of fowls seem more prone to lay eggs so marked 

 than others, and with a little trouble a race might no doubt 

 be produced which would lay eggs as regularly and as 

 permanently spotted as those of the Guinea Fowl. The 

 occasional marks on some of these eggs might, perhaps, be 

 regarded as opening up the still more obscure question of 



