.A Peculiar Character Referable to the Base of the Skull in Pandion. — 
As is well known, in all ordinary birds the anterior orifice or orifices of 
the eustachian tubes open, mesially, at the nether aspect of the base of 
the sphenoidal rostrum, just in front of the basitemporal region. This 
common or double aperture is often underlapped by a lip of bone, while 
the walls of the tubes themselves are usually completely ossified. Now 
in some Accipitres these walls, anteriorly, are not completed in bone, but 
in the dried skull exhibit more or less of an open tract. Pandion is re- 
markable in having the anterior openings of its eustachian tubes entirely 
closed , and it will be interesting to know whether this at all modifies the 
sense of hearing in this bird. The character is present in three different 
skulls of adult specimens that I have examined, so it is presumably con- 
stant, and, at the present writing, so far as I am aware it stands unique 
among birds. 
Since writing the above paragraph, Mr. F. A. Lucas, of the U. S. 
National Museum, has very kindly sent me the head of a recently killed 
specimen of Pandion , and I have had the opportunity of dissecting it 
while the parts were perfectly fresh. They confirm what I have written 
above, inasmuch as the anterior aperture or apertures of the eustachian 
tubes do not open in the middle line of the cranium above the anterior 
spine of the basitemporal. But the osseous antero-lateral walls of the 
passages in question are patulous, at some distance, upon either side, 
from the median line, and the fleshy parts of the eustachian tubes commu- 
nicate therewith. By means of a fine bristle, I found either passage com- 
municated, as usual, with the middle ear, and so there can be no question 
as to the functional status of those organs in the Osprey. The external 
auricular cavities, however, are small, and in either one I found a loose 
plug of some size, of a substance that had the appearance of a blackish 
wax, and this is sometimes seen in other large birds. — R. W. Shufeldt, 
Takoma , D. C. j^UXkl, 
Auk, 8, April, 1391, p, 
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