268 Letters, Extracts, and Notes. [Ibis 



List of other Ornithological Publications received. 



MuLLExs, W. II. & SwANN, II. K. A Bib.iogiapby of British Orni- 

 thology. (Part V. Loudon, 1917.) 

 WiTHEKBY, H. F. On some Results of ringing Song-Thrushes, Black- 

 birds, Lapwings, and Woodcock. (' British Birds,' Vol. x. No. 9. 

 London, 1917.) 

 The Auk. (Vol. xxxiv. No. 1. Cambridge, Mass., 1917.) 

 Avicultural Magazine. (Third Series, Vol. viii. Nos. 1-5. Loudon, 



1917.) 

 Bird Notes. (New Series, Vol. viii. No. 1. Ashbourne, 1917.) 

 British Birds. (Vol. x. Nos. 9, 10. London, 1917.) 

 The Condor. (Vol xix. No. 1. Hollywood, Cal., 1916.) 

 The Irish Naturalist. (Vol. xxvi. Nos. 1-3. Dublin, 1917.) 

 Journal of the Federated Malay States Museum. (Vol. vii. pt. 2, 



Singapore, 1916.) 

 Revue Fran9aise d'Oruithologie. (Nos. 93, 94. Orlt^ans, 1917.) 

 The Scottish Naturalist. (Nos. 61-63. Edinburgh, 1917.) 

 The South Australian Ornithologist. (Vol. iii. pt. 1. Adelaide, 1917.) 



XVI. — Letters, Extracts, and Notes. 



Colours of the Eggs and the Nests of Birds. 



Sir, — I write to correct a wrong impression of my view 

 on ''Coincidence^^ and mimicry Avhich may have been left 

 as the result of an omission (already referred to) from my 

 April paper, and of the fact that the full explanation of 

 the egg-plate in the succeeding article (October) reached 

 you when the latter was already in paged proof. 



The view suggested in these two places was, briefly, that 

 variation in mouths and eggs (and, 1 believe, elsewhere) is, 

 to an immense extent, not lateral, so to speak, but backward 

 and forward along the line of already-accomplished evolu- 

 tion — a matter, probably, of the suppression or restoration 

 in ontogeny of particular colour-changes corresponding to 

 particular ancestral stages, intermediate as well as terminal. 



