Methods of preparing Natural Skeletons of Birds . 55 
in question was in immature winter plumage, I could not deter¬ 
mine the species. 
87. Larus audouinii, Temm. Audouin's Gull. 
Gould’s Birds of Europe, vol. v. pi. 438. 
On two or three occasions, at a considerable distance above 
Cairo, I noticed a large Gull with a bright red bill, which I be¬ 
lieve to have been Larus audouinii. I never succeeded in pro¬ 
curing a specimen. 
IV.— On the different Methods of preparing Natural Skeletons 
of Birds. By T. C. Eyton, E.Z.S., &c. 
I propose in this paper merely to state the different methods 
which I have employed in preparing the natural skeletons in my 
collection. Not that I entirely object to artificial skeletons; but 
I prefer natural, particularly if purchased from dealers, as the 
former are so very liable to be adulterated, if I may so apply the 
word. I have now before me a beautifully mounted skeleton of 
a Circus, purchased of a dealer, which has two left metatarsi. 
Birds generally come into collectors' hands either fresh with 
the flesh on, or partially cleaned and without having been 
macerated, or partially cleaned and having been also macerated. 
In the first case, I always remove as much of the flesh as I con¬ 
veniently can, and macerate the skeleton in water, which has a 
small piece of the flesh, previously removed, placed in it, until 
the flesh which remains on the bones becomes soft and easily 
scraped off. After this I place the skeleton in clean water, and 
change the water frequently until it ceases to become discoloured. 
I then place the skeleton in a solution prepared in the following- 
way :—Make a saturated solution of common alum, and when 
cool dilute it with an equal quantity of water, and add to it half 
an ounce of common salt for every half-pound of alum. This 
solution converts the ligaments into a species of leathery sub¬ 
stance, and also destroys the colour of any blood that may have 
penetrated the bones. The time that is required to effect this 
varies according to the state and size of the skeleton. If it be 
clear of blood, twenty-four hours will be sufficient; but some- 
