186 MR. W. K. PARKER ON THE OSTEOLOGY 
in the possession of Dr. Clarke, of Cambridge. Again, it would be interesting to know 
whether the wild Pelican has any non-pneumatic bones ; also the Horn-bill. I should 
suppose not, however. The economy of osseous substance in the skeleton of Pelecanus 
onocrotalus is so great that Dr. Fritsch of Prague declared to me, with great fervour, 
of a specimen in his collection, that ‘‘ you lay it on your hand, and it actually weighs 
nothing.” Now, in the ‘‘ Pluvialine ” (e. g. Vanellus cristatus, Charadrius hiaticula, &c., 
only the cranium proper contains air. Their long-billed, probing relatives (e. g. Nume- 
nius arquatus, Tringa cinclus, Limosa rufa, Totanus calidris) have a similar state of the 
skeleton. The Gulls (e.g. Larus canus, Gavia ridibunda) and the Mergansers (e. g. 
Mergus albellus) have the head and the vertebre, as far as to the thick part of the 
sacrum, pneumatic: in these birds the ribs, the sternum, and all other parts are fatty. 
In the typical “ Anatine ” (e.g. Querquedula caudacuta, Cygnus olor) the sternum and 
humerus also receive air. In that near relative of the Pelican the Cormorant, the 
bones seem to be entirely medullary. Many other Palmipeds have very fatty skeletons, 
especially the Divers, from the little Dabchick (Podiceps ewropeus) to the huge Pen- 
guins. In the Pluvialine and Tringine birds the thick branches of the trigeminal nerve 
are imbedded in fat-cells; so that the facial part of the skull is oily. In the larger 
‘“Waders” there are more pneumatic bones. In the Herons the tail-bones, the 
scapulz, clavicles, and coracoids, and all the limb-bones contain marrow, except the 
humeri. The furculum contains air, however, in the Adjutant and the Baleniceps, as 
also do the caudal vertebre. The Trumpeter (Psophia) agrees with the Heron, save 
that in it the broad coracoids are pneumatic. In the Hawks (Falconinz) even the 
os femoris contains air, but not, as a rule, the caudal vertebrae. In the Owl the thigh- 
bones are oily, as they are in most of the arboreal ‘“‘ Perchers,” ‘‘ Creepers,” and 
‘‘ Climbers,” although in them the cranial, facial, and trunk-bones are pneumatic. 
In birds that ‘‘do business in great [salt] waters” we find the most oily skele- 
tons; and yet we all well know that some of the most graceful aérial birds belong to 
this class, both among the “ Waders,” “‘ Swimmers,” and “ Plungers.”’ But the plung- 
ing Gulls and the wading Plovers are better fliers than many of the beautiful ‘‘ Ana- 
tine” that 
“Row their state, with oary feet.” 
Yet there is no very definite rule with regard to the connexion between pneumaticity of 
the bones and power of flight. All the salt-water birds have large nasal or supraorbital 
glands, for the sake, undoubtedly, of the delicate Schneiderian membrane. The iso- 
morphs of the Cetacea (the Penguins) might be expected to have a coarse, fatty, non- 
ornithic skeleton, and they have such a framework ; yet its teleology is as consummate 
as that of the Humming-bird or the Swift. The, axillary air-cell pushes itself into the 
head of the humerus internally and below the deep expanded portion, in many birds, 
especially the ‘ Anatine ”’; even where the humerus is medullary, as in Mergus, this 
large pit still exists, although the air-cell does not enter the bone-cavity. In the Pigeon 
