1922.] On Species and SuI)S/)ecies. 179 



remains of a iiost with fragments o£ shells was discovered, 

 we saw no sign of a living bird. The stupid tameness oi' 

 this species threatens its extermination, unless it is able to 

 retain a footing on the east side. Possibly the open winter 

 of 1920-21 with the comparative absence of snow, induced 

 the birds to leave their old haunts and migrate to fresh fields, 

 unless, indeed, it has been locally exterminated. 



IX. — Species and Subspecies. 

 By Percy R. Lowe, M.B.O.U. 



One of the chief reasons which induced mo, in collabora- 

 tion with Mr. Mackworth-Praed (Ibis, 1921, pp. 341-347), 

 to chase the hare started by Mr. Loomis in the pages of ' The 

 Ibis' (1920, pp. 964-966) on the subject of subspecies, was 

 to call attention to the opinion held by us, that ornitholo- 

 gists in general did not apparently sufficiently distinguish 

 between mutational or discontinuous variations which cha- 

 racterised one form of subspecies and continuous or environ- 

 mental variations which charactm-ised another form. 



If I may venture, in flat defiance of the example of the 

 angels, to [)lunge once more into the discussion, I would 

 like to give one or two concrete examples by way of illus- 

 trating what avo, my own j)ersonal views on the matter. 



A. As examples of discontinuous or nnitational subspecies 

 I may quote the following, taken at random : — 



(1) Plnvialis apricarius oreop/iilus Meinertz. which has 



just recently been described (Bull. B. 0. C. 

 vol. xlii. 1921, p. 6). 



(2) Fodiceps cristatus infuscatus Salvad. 



(3) Quer<juedula discors albinucha Kennard, Auk, 



xxxvi. J 919, pp. 459-460. 

 Examining these in detail and confining myself to a single 

 ditferential character in each, we find that : — 



In J-'luvialis a. oreophilus the narrow but well-defined 

 black frontal band present in P. a. apricarius is absent in 

 the British breeding race {cf. Bull. B. 0. C. loc. cit.). 



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