Fam. VI. PHASIANIDAE.–Of really distinct Sub-families this group may be said to possess three, (1) the _Numidinae_, or Guinea-fowls, (2) the _Meleagrinae_, or Turkeys, and (3) the _Phasianinae_, or Pheasants, Partridges, and Grouse; it is, however, customary to class the Grouse apart as _Tetraoninae_, though a difficulty at once arises in drawing the line of demarcation. For example, Huxley[150] considered _Caccabis_, _Francolinus_ and _Coturnix_ Galline, _i.e._ Phasianine; Dr. Gadow[151] makes them Tetraonine; while Mr. Ogilvie Grant[152] agrees with the former, but does not make these genera the link between the sections. Mr. Grant's view may be conveniently followed, but the division is in any case arbitrary. As a matter of further convenience a Partridge group (_Perdicinae_) may be formed, and the "American Partridges" may stand apart as _Odontophorinae_. Passing mention should be made of the economical importance of this Family as a factor in our food-supply, whether in the wild state as game, or in the domesticated as poultry; for almost inconceivable numbers of birds are bred, exported, or used for eating in their native countries, while the value of domestic fowls' eggs can best be estimated by imagining the consequence of a failure in the production. Man's custom herein is no doubt guided by the ease with which most of the species are secured or reared, and by the great development of the pectoral muscles or "flesh of the breast." The body is decidedly heavy, the head usually rather small, and the neck fairly long. The bill is comparatively short and stout–especially in _Ithagenes_, _Dendrortyx_, and elsewhere–but may be more elongated, as in _Lophophorus_ and _Euplocamus_; the maxilla {199}being curved, and overhanging the mandible, which exhibits two serrations on each side in the Odontophorinae. The metatarsus is strong and relatively short in Grouse and many Partridges, but in Pheasants and similar forms it is much longer; the feathering descends to the toes in the Tetraoninae, except _Bonasa_ and _Tetrastes_, the digits themselves being clothed in _Lagopus_, naked and pectinate at the sides in the remaining genera. No other members of the Family shew pectinations or have the metatarsus feathered, save _Lerwa_, where it is half covered. The hallux, invariably elevated, has only a rudimentary claw in _Rollulus_, _Melanoperdix_, and _Caloperdix_; _Arboricola_, _Dactylortyx_, and _Cyrtonyx_, on the contrary, have particularly long and somewhat straight claws. Spurs are of frequent occurrence on the feet of the males, though rare in the females, some species possessing as many as three pairs; they are never found in the Tetraoninae or Odontophorinae, and are represented by mere knobs in _Acryllium_ (Numidinae). The wings are short and rounded, with ten primaries and from twelve to nineteen secondaries, both decreasing in length as they near the middle of the wing, which has thus a bilobed appearance when expanded.