The sternum is long, especially in _Sula_, while the large head and short thick neck of _Phaëthon_ and _Fregata_ may be contrasted with the small head and remarkably long neck of _Phalacrocorax_, and still more of _Plotus_; _Sula_ and _Pelecanus_ being moderate in {71}both respects. The bill, which is more or less compound, is long, pretty straight, and generally compressed: in _Phaëthon_ and _Sula_ it is strong, conical, and pointed; in _Phalacrocorax_ either stout with a long hooked nail, or less robust with the hook at the tip shorter, the sides being scabrous; in _Fregata_ similar, in _Plotus_ slender and tapering, in _Pelecanus_ weak, much flattened, hooked, and scaly. The maxilla is furrowed in _Sula_, _Pelecanus_, and _Phalacrocorax_, with the median part concave in the latter, while the cutting edges of both mandibles are serrated in _Phaëthon_, _Sula_, and _Plotus_. The legs are placed far back, especially in _Phalacrocorax_, the tibiae being partly bare in _Phaëthon_ and _Pelecanus_, but feathered in the other forms, of which _Fregata_ has the clothing continued to the toes. The metatarsus is short, stout, and compressed, that of _Fregata_ being extremely abbreviated, as in the Spheniscidae; it is entirely covered with hexagonal scales, becoming almost reticulated behind, while the toes exhibit distinct transverse scutes in _Phalacrocorax_, and have a similar tendency elsewhere. The hallux, which is somewhat elevated in _Phaëthon_, is turned inwards or forwards, and is connected with the remaining toes by full webs, except in _Fregata_, where the membranes are excised to about half their extent; this unique "Steganopodous" foot giving the name to the whole group. The stout curved claws–weaker in _Fregata_–are of medium length, that of the middle digit being serrated on the inner side in the last named, _Sula_, and _Phalacrocorax_. The wings are long and pointed, reaching their maximum in _Fregata_, their minimum in _Phalacrocorax_, and having a very ample spread in _Sula_ and _Pelecanus_. There are eleven primaries, and from fifteen to twenty-nine incurved secondaries, which may even exceed the former. In _Pelecanus_ the short, broad, roundish tail consists of from eighteen to twenty-four soft acute rectrices, but in the remaining genera the feathers are strong and stiff, being particularly rigid in _Phalacrocorax_ and _Plotus_: _Phaëthon_ has sixteen, which are moderate and graduated, with a long filiform median pair in the adult; _Sula_ and _Phalacrocorax_ from twelve to fourteen in a more or less wedge-shaped formation; _Fregata_ twelve, arranged in a fork; while _Plotus_ has the same number, forming a fan, the webs being very broad and showing curious transverse corrugations in mature birds, found also on the scapulars. The tail is fairly long in the four last {72}mentioned, except in some members of _Phalacrocorax_. The V-shaped furcula ancyloses with the sternum in some of the Sub-Order, but