394 G. P. BULMAN [may 1899 



nients, which are urgently required, establish it beyond doubt, 1 think 

 Weisniann is fully justified in disregarding it. 



" Hybrid Oology." 



By this term (a very clumsy one, I confess — but faute dc mieux !) 

 I wish to denote that extraordinary phenomenon, which has been 

 so often reported in connection with the eggs laid by a bird when 

 fertilised by the cock of a different species. I refer to the supposition 

 that at the time of fertilisation, not only is the ovum fertilised, but 

 that part of the oviduct which secretes the shell is affected in such a 

 manner, that the ovum on passing through is provided with a shell 

 which partakes of the tints of the eggs laid by the cock's own species — 

 and not only the tint but also the microscopic structure. 1 Instances 

 of this kind are mentioned by Dr. Hans Gadow in Bronn's Thierreich, 

 vol. Aves, p. 874, and by Nathusius (Journal f. Omithologie, 1874, 

 p. 1), and a few have come to my own knowledge. A friend has 

 informed me of a case in which he kept some fowls of the Orpington 

 variety separate for a time, when they laid eggs of a buff (the ordinary) 

 tint. He then allowed them to run loose in a large yard, in which 

 were fowls of all sorts ; but after a few months he again confined 

 them in a separate pen. But for several weeks after the eggs laid by 

 them were pure white. The Orpington breed having been so lately 

 developed, I should have thought that they were simply reverting to 

 ancestors of a white-egg-laying variety, had I not heard at the same 

 time of two similar cases regarding black Spanish, a comparatively old 

 breed. Mr. Meek tells me that in the magnificent collection of Mr. 

 W. Mark Pybus, Newcastle-on-Tyne, he saw a clutch of eggs which 

 had been laid by a black Spanish hen when fertilised by the black 

 cock. While the eggs showed both in form and texture the well- 

 known properties of those laid by the hen's species, in colouring they 

 were almost indistinguishable from the cock's. 



In the case of " hybrid oology," as in that of xenia, experiments 

 have not been conducted to any great extent, and in all probability 

 the supposed effects have arisen from some other cause, such as a 

 previous cross. 



I do not think we ought to rest until these three hypotheses are 

 either proved to be justifiable, or, after an overwhelming number of un- 

 successful experiments, relegated to the land of myths. 



1 A. Newton, ' ; A Dictionary of Birds," Part I. p. 190. 



cullercoats, 



Northumberland. 



