The primitive Neotropical Order Tinamiformes, with the Sub-Order TINAMI, and sole Family TINAMIDAE or CRYPTURIDAE, is classed here in accordance with Dr. Gadow's carefully-weighed decision;[142] yet the position must not be considered absolutely certain, most systematists placing it near the Ratitae. The complete fusion of vomer and palatine bones is unique among Birds, though partially noticeable in _Dromaeus_ and _Apteryx_; the conformation of the skull, the single head of the quadrate, the separation of the ischium and ilium, the absence of a pygostyle, the reduced tongue, the functionless tail, the gait and bearing are Struthionine features; but other points of structure, the pterylosis and the habits generally, are Galline. The furcula is U-shaped; the sternum long and slender with well-developed keel; the head small; the neck thin and elongated with short plumage; the beak fairly strong, varying in length, and composed of more than one piece, the culmen being flattened and usually arched; the moderate metatarsus is transversely or hexagonally scutellated, and may be rough or smooth behind, while the hallux–wanting in _Calopezus_ and _Tinamotis_–is elevated, and the anterior toes are long or short, with moderate claws. The short wings are concave and rounded, with ten primaries and from thirteen to sixteen secondaries; the {183}abbreviated tail possesses ten very weak feathers, hidden by the coverts in _Tinamus_, _Nothocercus_, and _Crypturus_, and hardly distinguishable from them in _Rhynchotus_, _Nothoprocta_, and _Nothura_, the coverts themselves almost forming a train in the male of _Taoniscus_. _Calodromas_ has twelve rectrices. The tongue is small and triangular, the crop is large and globular, the after-shaft is rudimentary or wanting; powder-down feathers occur near the rump, and the down of the adults is sparing, while that of the nestlings, which run from the shell, is simple, as in Ratite birds, and of a buffish-brown or chestnut colour, often relieved by black markings and white streaks.