PROCEEDINGS OP THE BRITISH ASSOCIATION. 
420 
the Channel islands : Anemone nemorosa^ Bromus asper^ Campanula (none 
of the genus), Hypericum hirsutum^ Listera ovata^ Betula alha, Caltha pa- 
lusfris^ Hahenaria chloranthus^ Helianthemmn vulgare^ Juncus glaucus, 
Of those common in England and rare in the Channel islands he had found 
Cardamine pratensis^ Lamium alburn^ Primula reris^ Ranunculus ficaria^ 
Mercurialis perennis. Of those rare in England and common in the islands, he 
had met with Orobanche ccendea^ Scroplndaria scorodonia, Lotus hispidus^ 
pjrodium moschatum^ Iris foetidissimus^ &c. 
Mr. Allis then read a paper ‘‘ On the Sclerotic Bones of the Eyes of Birds 
and Reptiles.” He began by adverting to the little attention this subject had 
received from naturalists and comparative anatomists. When he commenced 
his investigations he had no idea of the difference in size, form, number, and 
texture these peculiar organs presented. He then made quotations from Cuvier, 
Blumenbach, Yarrell, Carus, and Buckland on this subject; and having- 
demonstrated the points of agreement and difference between his observations and 
those of the authors above quoted, he stated 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, beautifully 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 over¬ 
lapping each other they present nearly an even surface, having one bone with both. 
depressions on its inner surface, and forming an interior key to the arch, another, 
having two depressions externally, and forming an exterior key. They form a 
defence and protection to the eye, and those birds which are pugnacious, 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 observed 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 Gallinidce the number varied from thirteen to seventeen; in the 
ColumbidcE they were small and feeble; in the Ostrich tribe they were large; 
in the Grallce small and feeble ; in the Scansores the same, and twelve or thirteen 
in num.ber; 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 Passerince they varied considerably, but were generally weak; in Reptiles 
they varied considerably in number, shape, and size. 
No. IR Yol. IL 3 L 
