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greater strength than the weak-billed or low-flying birds ; and 

 the same remark holds good with the water birds, on comparing 

 those that take their food on or near the surface of the water, 

 with those that dive ; among which class are to be found the 

 strongest bones. 



Another subsidiary use, is that of altering the convexity of 

 the Cornea as mentioned by Dr. Buckland. 



I have eight specimens of diurnal Rapacidse ; the Golden 

 Eagle affords an example of a bony ring of greatly increased 

 strength in a bird that takes a lofty flight and' follows its prey 

 with great velocity : it is a smaller bird than the white tailed 

 Eagle, yet the bony ring is larger, more convex, and the indivi- 

 dual bones much stronger. The King Vulture and Lammer- 

 geyer have the rings stronger than their congeners ; and the 

 Secretary also has it very strong, but with its habits of flight I 

 am unacquainted ; of this series, three have fourteen bones, 

 four has fifteen, and one has sixteen. 



Here are five specimens of Owls ; two belong to the great 

 Horned Owl : one set of the detached bones shews the upper, 

 the other set the under surface of these bones ; the principal 

 use of the elongated tube appears to be, to bring the eye beyond 

 the loose feathers of the head ; if the bones were no longer 

 than in the generality of birds, the eyes would be so buried in 

 the feathers that the bird would only be able to see objects 

 straight before it. The bones of the Barn Owl are not larger 

 than those of the little Scops, though the bird itself is nearly 

 three times as large ; they are not required to be so long in the 

 Barn Owl on account of the large circular disk of close and 

 short feathers that surrounds each eye. The bones of the Owls, 

 instead of being, as stated in general terms by Cuvier, hard, 

 flat and thin, are very soft and porous ; as is also the case in 

 those of the Caprimulgidae, and those of the great Horned Owl 

 are also of considerable thickness. 



I have seven specimens of Gallinida? ; one of these has 

 thirteen bones ; four have fourteen ; one has fifteen ; and one 

 has seventeen ; the ring in most of these is strong. 



Of Columbidse, I have three specimens, each of which has 



