206 THE ZOOLOGIST. 
hibernicus it forms a patch or stripe extending from between 
the fore limbs backwards, sometimes for a length of one inch 
and a half. 
I regret that, owing to the scarcity of material, it has not yet 
been possible to make a complete examination of the osteological 
characters, if any, of M. hibernicus. The results of this and of 
further general research and comparisons are deferred for a 
future occasion. 
A male having the white stripe, and a female, are figured, 
both Hebridean specimens, and have been kindly presented to 
the Museum of Science and Art, Edinburgh. 

ON THE PRODUCTION OF COLOUR IN BIRDS’ EGGS. 
By A. H. S. Lucas, M.A., Oxon., B.Sc. Lond.* 
THE question of the cause of the coloration of birds’ eggs 
has often been referred to, but has not, to my knowledge, been 
adequately treated of in any work on Oology. Perhaps we may 
consider the latest views on the subject to be those enunciated 
by Mr. H. Seebohm in his lecture at the London Institution, 
December 20, 1886.+ I had published in the Melbourne 
‘Leader’ of December 26, 1885, a popular account of the 
colours of Australian birds’ eggs, in which I advanced sug- 
gestions which seemed to me to throw light on the subject. 
After reading the abstract in ‘Nature’ of the interesting 
lecture by this high authority, I have thought it worth while to 
make a more formal scientific record of the ideas broached 
in the ‘ Leader.’ 
My hypotheses may well be encountered with criticism, but 
they do serve at least very conveniently to connect a multitude 
of facts together. The antiquity of the Australian Avi-Fauna, 
and the preservation of ancient types, render a comprehensive 
consideration of Australian eggs of the greater value. My 
suggestions have been founded on studies of large collections, 
and after a certain amount of experience in the field. Australian 
eggs yield a, rich abundance of facts which are of scientific 

* From the Trans. and Proc. Roy. Soc. Victoria, vol. xxiv, pp. 52—60. 
+ Printed in ‘ The Zoologist,’ 1887, pp. 187—139, 
