74 



FIELD ORNITHOLOGY 



following points require attention ; the breast-bone often has long 

 slender processes behind and on the sides (the common fowl and the 

 ptarmigan are extreme illustrations of this, as shown in the figures), 

 liable to be cut by mistake for ribs, or to be snapped ; the shoulder- 

 blades usually taper to a point, easily broken off ; the merrythought 

 is sometimes very delicate or defective. When travelling, it is 

 generally not advisable to make perfect preparations of either skull 

 or sternum ; they are best dried with only superfluous flesh removed, 

 and besprinkled with arsenic. The skull, if perfectly cleaned, is 

 particularly liable to lose the anvil-shaped, pronged bones that hinge 

 the jaw, and the freely movable pair that push on the palate from 

 behind. Great care should be exercised respecting the identification 

 of these bones, particularly the sternum, which should invariably 

 bear the number of the specimeii to which it belongs ; the label 

 should be tied to the coracoid bone. A skull is more likely to be 

 able to speak for itself, and, besides, is not usually accompanied by 

 a skin ; nevertheless, any record tending to facilitate its recognition 

 should be duly entered on the register. There are methods of 

 making elegant bony preparations. You may secure very good 

 results by simply boiling the bones, or, what is perhaps better, 

 macerating them in water till the flesh is completely rotted away, 

 and then bleaching them in the sun. A little potassa or soda 

 hastens the process. With breast-bones, if you can stop the process 

 just when the flesh is completely dissolved, but the tougher liga- 

 ments remain, you secure a "natural" preparation, as it is called; 

 if the ligaments go too, the associate parts of a large specimen may 

 be wired together, those of a small one glued. I think it best, 

 with skulls, to clean them entirely of ligament as well as muscle ; 

 for the underneath parts are usually those conveying the most 

 desirable information, and they should not be in the slightest 

 degree obscured. Since in such case the anvil-shaped bones, the 

 palatal cylinders already mentioned, and sometimes other portions 

 come apart, the whole are best kept in a suitable box. I prefer to 

 see a skull with the sheath of the beak removed, though in some 

 cases, particularly of hard-billed birds, it may profitably be left on. 

 The completed preparations should be fully labelled by writing on 

 the bone, in preference to an accompanying or attached paper slip, 

 which may be lost. Some object to this, as others do to writing on 

 eggs, that it defaces the specimen ; but I confess I see in dry 

 bones no beauty but that of utility. 



" In many families of birds, as the ducks (Anatidce), the trachea 

 or windpipe of the male affords valuable means of distinguishing 

 between the different natural groups, or even species, chiefly by the 

 form of the bony labyrinth, or bulla ossea, situated at or just above 

 the divarication of the bronchial tubes. A little trouble will enable 



