ANATIDZ, GEESE, DUCKS, ETC. 279 
slight nasal aperture remains. Sometimes the top of the skull shows crescentic 
depressions for lodgment of the supraorbital gland, the secretion of which lubricates 
the nasal passages; but this feature is never so marked as in most of the pisciv- 
orous swimmers. The sternum is both long and broad, more or less transverse 
posteriorly, with a simple notch or fenestra on each side; sometimes its keel is 
curiously hollowed out for a purpose stated beyond. The vertebrae vary a good 
deal in number, owing to the variability of the cervicals, which run up to 23 in some 
swans. The pelvis is ample, arched and extensively ossified, with small foramina, 
showing nothing of the straight, constricted, largely fenestrated figure prevalent 
among lower water-birds. 
The tongue is large and fleshy ; its main bone (glosso-hyal) is highly developed ; 
its sides show a fringe of processes corresponding to the lamelle of the bill. The 
gullet is not so ample as in the flesh-eating swimmers. The gizzard resembles that 
of a fowl in its shape and great muscularity ; the muscles are deep-colored, and well 
show the typical disposition of large hemispherical lateral masses converging to 
central tendons. The cceca vary with the genera according to food; they are very 
long—12 or 15 inches—in some of the herbivorous species. The male genital 
armature merits special notice. ‘‘In some Natatores which copulate on the water 
there is provision for more eflicient coitus than by simple contact of everted cloacee ; 
and in the Anatide a long penis is developed. It is essentially a saccular produc- 
tion of a highly vascular part of the lining membrane of the cloaca. * * * In 
the passive state it is coiled up like a screw by the elasticity of associated 
ligamentous structure. * * * A groove commencing widely at the base follows 
the spiral turns of the sac to its termination; the sperm ducts open upon papillee 
at the base of this groove. This form of penis has a muscle by which it can be 
everted, protruded and raised.” (Owen.) Among the most interesting structures 
of the Anatide are the curious modifications of the windpipe, prevailing almost 
throughout the family. In a number of swans, this organ enters a cavity in the 
keel of the sternum, doubles on itself and then emerges to pass to the lungs, forming 
either a horizontal or a vertical coil. In some geese the windpipe coils between the 
pectoral muscles and the skin. These vagaries of the windpipe are not, however, 
confined to the present family, occurring in some of the cranes, certain Galline, 
and also, it is said, in the curious snipe, Rhynchwa capensis. In most of the ducks, 
furthermore, and in the mergansers, the lower larynx is a singularly enlarged and 
complicated affair; several of the lower rings of the trachea being soldered together 
and greatly magnified to produce a large irregularly shaped capsule. Its use is 
not known; in some sense it is a sexual character, since it is only fully developed 
in the male; it varies greatly in size and shape in different species. Finally, it 
should be added, that the pterylosis of the family is perfectly definite, a certain type 
of tract-formation prevailing throughout, with very slight minor modifications. 
It is not easy to overrate the economie importance of this large family. It is 
true that the mergansers, some of the sea ducks, and certain maritime geese, that 
feed chiefly upon animal substances, are scarcely fit for food; but the great majority 
afford a bounteous supply of sapid meat, a chief dependence, indeed, with the 
population of some inhospitable regions. Such is the case, for example, in the 
boreal parts of this continent, whither vast bands of water-fowl resort to breed 
during the fleeting arctic summer. Their coming marks a season of comparative 
plenty in places where hunger often pinches the belly, and their warm downy 
covering is patched into garments almost cold-proof. 
The general traits of the anserine birds are too well known to require more than 
