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British Association for the Advancement of Science. 289 
The Sclerotic Bones of the Eyes of different Birds and Rep- 
tiles.—Mr. Allis read a paper ‘ on the sclerotic bones of the eyes of 
different birds and reptiles.’ He stated, that he believed the sub- 
ject of his paper had not received much attention from comparative 
anatomists. With regard to their number, Cuvier had stated them 
to be twenty, but he had never found more than seventeen, and 
sometimes even only one. He then quoted the observations that 
had been made on this subject by Blumenbach, Cuvier, Carus, Yar- 
rell and Buckland, and proceeded to state, that ‘‘the shape of the 
individual bones is so various, that it cannot be given in any general 
terms; the external edge of the bones is, in most instances, beauti- 
fully serrated, but the serration is not visible in the bony ring: this 
serration being generally destroyed by the process of boiling that is 
necessary to their preservation. ‘The rings generally overlap each 
other, there being a depression on the under side of one bone, and 
a precisely corresponding one on the upper side of its fellow; so 
that when overlapping each other they present nearly an even sur- 
face, having one bone with both depressions on its inner surface, 
and forming an interior key to the arch; another, having two de- 
pressions externally, and forming an exterior key. They form a 
defense and protection to the eye, and those birds which are pug- 
nacious, or have a peculiarly rapid flight, or vary their attitude in 
flying, &c., have the sclerotic rings of larger size and more convex 
form, and are of greater strength; the same remark holds good with 
respect to water-birds. Another use of these bones, is, altering the 
convexity of the cornea, as mentioned by Dr. Buckland.” He 
then exhibited a great number of specimens of these bones, and ob- 
served, that in the eagles and vultures they were strong and large, 
and varied in number from fourteen to sixteen; in owls, soft and 
porous, and not hard, as Cuvier had stated; in the gallinide the 
the number varied from thirteen to seventeen; in the columbide 
they were small and feeble ; in the ostrich tribe they were large ; 
in the gralle small and feeble; in the scansores the same, and 
twelve or thirteen in number; in the swimmers they were weak and 
small, and from twelve to sixteen in number; in divers, strong and 
large, and twelve to fifteen in number; in the passerine they varied 
considerably, but were generally weak ; in reptiles they varied con- 
siderably in number, shape and size. 
Chemical Composition of Vegetable Membrane and Fibre.—A 
paper ‘on the chemical composition of vegetable membrane and 
