Zoological Society. 1 45 



as roofing slate up to its line of contact with the incumbent clay j 

 but where the diluvium is of sand or gravel, admitting ready access 

 of water through it to the subjacent slate rock, the slate is often in 

 a shattered state, and bent and decomposed to the depth of many feet 

 below the line of contact. 



At the close of this Meeting, which terminated the Session, the 

 Society adjourned till Wednesday the 2nd of November, 



ZOOLOGICAL SOCIETY. 



May 31, 1831. N. A. Vigors, Esq. in the Chair. 



At the request of the Chairman, Mr. Gould exhibited a specimen 

 of the male of the Urogallus medius ; the Tetrao hybridus of Gmelin 

 and[ Dr. Latham, and the Tetrao medius of M. Temminck. 



Mr.Yarrell observed that this individual, with one other example of 

 the same rare species, also a male, was found among a considerable 

 number of tlie Tetrao Urogallus of both sexes, brought from Nor- 

 way by a boat partly laden with lobsters for the London market. 

 Some of the older writers considered this bird to be a hybrid pro- 

 duced between the Wood Grouse and the Black Grouse, and had 

 named it accordingly : modern authors have, however, established 

 its distinction as a species ; and the female and its egg are now 

 known. Notwithstanding the general resemblance between these 

 two large Wood Grouse they are decidedly and very obviously dif- 

 ferent. In the Tetrao medius the beak is black ; the shining fea- 

 thers on the front of the neck and breast are of a rich Orleans-plum- 

 colour ; and of the 18 feathers of the tail the outer ones are the 

 longest. In the Cock of the Wood the beak is white ; the feathers 

 on the front of the breast are of a dark glossy green ; and the centre 

 feathers of the tail are the longest. 



The organ of voice in the Tetr. medius is peculiar. The trachea 

 of this bird and that of the Tetr. Urogallus were exhibited ; and Mr. 

 Yarrell pointed out that the trachea of the Tetr. medius, eleven 

 inches in length, has no loo.se fold, like that of the Tetr. Urogallus, 

 but descends in a straight line to the lungs. From the thyroid car- 

 tilage two pairs of muscles follow the course of the trachea, one pair 

 firmly attaclied to the trachea itself, the second pair suspended 

 loosely in the cellular tissue. Both these pairs of muscles, after an 

 extent of eight inches, are lost in a membranous expansion, form- 

 ing a sheath, which invests the inferior fourth portion of the trachea, 

 and from which sheath one muscle only on each side is sent off, 

 immediately above the bifurcation of the bronchia, to be attached 

 to the inner surface of the sternum. 



The stomach is a true gizzard of great muscular power, and the 

 intestines and caeca, as in all the Grouse tribe, are very long : the 

 ccBca in the present instance measured each three feet in length. 



There is reason to believe that this bird inhabits the Apennines 

 as well as the more northern localities assigned to it. Mr. fox in 

 his ' Synopsis of the Newcastle Museum' quotes a note of the late 

 Mr. Tunstall which states that " he knew some old Scotch gentle- 

 men who said they remembered, that when young, there were in 

 Scotland both the Cock of the Wood, and the Tetr. hybridus." 

 N.S. Vol. 10. No. .56. Aug. 1831. U Mr, 



