The primaries usually increase in length before decreasing, but in some cases the exterior quill is the longest, while in _Falcipennis_ two or three of the outer feathers are sickle-shaped, and in _Argus_ the secondaries are enormously developed. The tail is extremely variable, being long and rounded in _Lophophorus_; long and sharp-pointed in _Phasianus_ and _Centrocercus_; moderate, broad, and rounded in _Lagopus_, _Odontophorus_, and so forth; similar but more truncated in _Meleagris_; short in most Partridges; and exceptionally abbreviated in many Quails. The coverts far exceed the tail in the Peacock, forming its splendid train, while they are much elongated in _Chrysolophus_, and to some extent in _Coturnix_, _Excalphatoria_, and _Ceriornis_ (_Tragopan_). In _Pedioecetes_ the two middle rectrices surpass the rest and terminate abruptly; in _Lyrurus_ the exterior feathers fork outwards; in _Crossoptilon_ and _Gennaeus_ the median plumes curve over the others; and in _Lobiophasis_ not only is this the case, but the rhachis extends beyond the webs, which are much reduced on the outer side of the lateral quills; in _Argusianus_ and _Rheinardtius_ the middle pair is extraordinarily lengthened. The whole tail is compressed or "vaulted" to a greater or less degree in _Gallus_, _Chrysolophus_, _Lophura_, _Acomus_, _Gennaeus_ {200}and _Crossoptilon_. _Excalphatoria_ is remarkable for possessing only eight rectrices; ten are found in _Microperdix_, and occasionally in _Synoecus_ and _Coturnix_; but the usual number is from twelve to twenty-four, while _Lobiophasis_ has thirty-two in the male and twenty-eight in the female. The nostrils are concealed by the feathering in the Tetraoninae alone, the aftershaft is large except in _Pavo_, the furcula is Y-shaped, the tongue sagittate, the syrinx tracheo-bronchial. The globular crop and muscular gizzard are decidedly characteristic, yet _Argusianus_ has been said to lack the former, and _Centrocercus_ the latter. In the male of _Tetrao urogallus_ and both sexes of _Guttera_ the trachea has a loop, which in the latter case passes through a cavity in the head of the furcula.