1866.] 



Dr. Davy on the Bursa Fabricii. 



97 



15. In anotlier, about three years and a half old, no traces of a bursa 

 could be detected. Its cloaca and oviduct were very large, as were also 

 those of the preceding. 



II. Pheasant (Phasianus colchicus). — In ten examined (seven males, 

 three females), with the exception of three (inferred to be old birds), the 

 organ in question was found. It resembled in structure that of the com- 

 mon fowl of from four to eight months old. In each instance it was empty, 

 merely wet with mucous fluid. These birds were shot in November, Decem- 

 ber, January, and February. Not knowing their precise age, but supposing 

 them to have been hatched in the spring, their bursa as to size was some- 

 what less than that of the common fowl. The smallest, that of a hen shot 

 in February, m.easured '3 inch by *2 ; it retained its plicated structure, and 

 freely communicated with the cloaca. 



III. Vartridge (Perdix cinerea). — Of this bird three specimens have 

 been examined. In one, apparently old, no trace could be found of a bursa. 

 In the other two, in which it occurred, it resembled in form and structure 

 that of the common fowl ; it measured '4 inch by -3. These were young 

 birds which had taken wing. 



IV. Turkey (Meleagris gallopavo). — In three instances of this bird, all 

 liatched in spring, one examined in October, one in December, one in 

 January, the bursa was found similar to that of the common fowl, and in 

 each nearly of the same size, about 1*5 inch by '7. 



V. Grouse (Tetrao scoticus). — In a young bird, not fully fledged, just 

 capable of a short flight, shot in the island of Lewis on the 12th of August, 

 expressly for the purpose of examination, the bursa was found small, about 

 the size of a pea. Air was found in its humeri, but only partially in its 

 femora. In two, both from Scotland, later in the season, no bursa could 

 be detected. Their femora contained air as well as their humeri. 



VI. Pigeon (Columba domestica). — In two full-grown males examined 

 in September, no trace v/as found of a bursa ; in other two (these younger 

 birds) the bursa was pretty large. 



VII. Buzzard (Falco buteo). — Of a young one taken from its nest on 

 the 9th of June, when about a fortnight old, the bursa was globular and 

 comparatively large, about '8 inch in diameter, non-plicated, and empty. 

 This nestling weighed 5193 grs. ; it was covered, except at the umbilicus, 

 where bare, with plush-like yellow feathers, thick, very closely set, equal 

 in weight to 647 grs. 



VIII. Sparrow-hawk (Falco nisus). — Of a young bird, pxamined on 

 the 31st of July, just capable of flight, weighing 3686 grs., its sternum 

 still cartilaginous, its humeri only partially filled with air, the bursa was 

 small. In another, a male, apparently an old bird, shot on the 8th of 

 March, no traces of bursa were found. It weighed 2836 grs. 



IX. Tawny Owl (Strix stridula). — Of a young one taken from its nest 

 on the 21st of June, when well fledged, but its quill-feathers not fully formed, 

 weight 4496 grs., the bursa was globular atid comparatively large, "7 inch 



