EXPERIMENTS WITH PIGEONS 89 



in support of the telegony hypothesis.' Nothing has 

 occurred which is not explicable on the theory of 

 reversion. 



Partly owing to a certain doubt or distrust which has 

 recently been expressed as to the existence of reversion, 

 and no doubt partly because it is reasonable to hold 

 that the phenomena of telegony may all be referred 

 to reversion, Professor Ewart has made some direct 

 experiments on this subject. Darwin, Tegetmeier, 

 and many others have made numerous breeding 

 experiments on pigeons, with the result that we may 

 say that the crossing of extreme forms usually tends 

 to reversion in the offspring. The ancestor of the 

 domestic pigeon is known with tolerable certainty to 

 have been the blue-rock pigeon, Columba livia. By 

 crossing a male barb-fantail and a female barb-spot 

 Darwin produced a bird 'which was hardly distin- 

 guishable from the wild Shetland species' of blue- 

 rock. In his description of this experiment, Darwin, 

 as Weismann points out, confines himself chiefly to 

 the coloration : he does not inquire how far reversion 

 also appears in the structure of the bird. This 

 question has been answered by one of Professor 

 Ewart's many experiments with pigeons. He crossed 

 a white fantail cock with the offspring of an owl and 

 an archangel. The fantail was pure white, with thirty 

 feathers in its tail, and was so prepotent as to produce 

 white offspring when mated with blue pouters. The 

 owl-archangel was more of an owl than an archangel. 

 One of the young of this complex pair had the 

 coloration of the Shetland rock pigeon, which has 

 a white croup and the wings in front of the bars a 

 uniform blue; the other resembled the Indian rock 

 pigeon in having a blue croup and the front part of 

 the wings chequered. In this second bird there was 

 complete reversion as to colour, and in the first, 

 wherever measurements were possible, there was 



