1922.] Letters, Extracts, and Notes. 217 



publication of tlie coUectcMl and analysed results -nill be 

 ail (jveiit of great importance to students of migration." 



Finally, it may be doubted vvlietlicr ornithologists are 

 as yet prcjjared to accept the evidence mentioned by 

 Mr. Robinson, to the extent oC regarding it as complete 

 and (inal proof that for the young to seek exactly the same 

 winter-quarters as their particular parents is a general rule 

 among migratory birds. The existing evidence, however, 

 does at least confirm the point of my original remark, 

 which was to the effect that this sort of question is 

 eminently suitable for investigation by the marking 

 method. 



A. Landsborough Thomson. 

 9 Addison Gardens, 



Kensington, W. 14, 

 17 October, 1921. 



A possible Mendelian variation in Nature. 



Sir, — Colonel Meiuertzhagen's paper on " Subspecies and 

 Evolution" (Ibis, 1921, p. 528) covers a wide field and 

 touches on many unsolved and controversial problems. 

 This note is concerned only with one comparatively small 

 point. In several passages Colonel Meinertzhagen states 

 or implies tiiat variations of the kind studied by the 

 ]Mendeliaiis are only known to occur under artificial 

 conditions. The exact breeding experiments by Avhich 

 Mendelian theories are tested must of necessity be under 

 artilicial control, but at least in the case of plants and 

 insects many of the characters which have proved to be 

 inherited after the Mendelian fashion were first found in 

 nature. As applied to birds, however, Colonel Meinertz- 

 hagen's contention is not without some foundation, since 

 domestic poultry are the only birds of which the genetics 

 have been at all adequately investigated. That is why it 

 may be worth while to suggest that the well-known montana 

 variety of the Common Partridge is a case of Mendelian 

 variation occurring in nature. 



