( 37-t ) 



Proceedings of the Royal Society of Edinburgh. 

 (Continued from last Number, p. 176.) 



1842, December 5. — Sir T. Makdougall Brisbane, Bart., 

 President, in the Chair. 



1. On the Construction of a New Music Hall. By Sir George 

 S. Mackenzie, Bart. 



December 19. — The Right Honourable Lord Greenock, Vice- 

 President, in the Chair. 



1. Letter on Terrestrial Magnetism, addressed to the Secre- 



tary. By Professor Hansteen of Christiauia. 



2. Notice of the occurrence in Scotland of the Tetrao medius, 



shewing that supposed species to be a hybrid. By James 

 Wilson, Esq. 



There exists in several northern continental countries a peculiar 

 kind of grouse, called by foreign naturalists Tetrao medius, on ac- 

 count of its exhibiting, as it were, a combination of the characters of 

 the wood-grouse or capercailzie on the one hand, and of the black- 

 cock on the other. It is never found except in countries inhabited 

 by the two species last named ; and as it presents a union of their 

 characters, several naturalists have inferred that it is not itself a 

 distinct kind, but a hybrid, resulting from the casual intercourse of 

 the other two. But most naturalists have maintained that it is a 

 distinct species, chietly upon the principle, that, in the wild state, 

 birds of different species do not intermingle sexually with each other. 

 Mr Wilson, however, having discovered that, in certain districts of 

 Scotland into which Lord Breadalbane has lately introduced the 

 canercailzie, and in which the black-cock previously existed in abund- 

 ance, this so-called intermediate grouse has also now made its appear- 

 ance, he draws the conclusion, that it is not a distinct species, but a 

 hybrid or mule. '• It had not been previously known in Scotland, 

 at least in our times, — it has not been introduced by any one from 

 abroad, — and yet here we now find it in the very districts inhabited 

 by the other two." Mr Wilson exhibited a specimen recently killed 

 on the estate of Dunira, and shewed its entii-e agreement Avith the 

 foreign T. medius, by comparing it with a specimen from Norway. 



3. On the Coloration of the Blood. By the late Daniel Ellis, 



Esq., F.R.S.E. Communicated by Dr Christison. 



