WHILE it is perhaps hardly correct to assert that the Emeus and Cassowaries, which comprise the present order, are actually the most primitive of the Ratites, it is beyond question that they must have arisen from the original procarinate stem at a point very near those which gave rise to the Ostriches and Rheas. In any event they now differ from them in a number of important particulars, such as the absence of the ambiens muscle and the possession of a distinct after shaft to the feathers; in fact, the latter is so enormously developed as to be of practically the same length and size as the main shaft. Another of the important differences is the extreme reduction of the wing in the members of the present group, for, as Dr. Stejneger says, it “could hardly become smaller without disappearing altogether externally.” There is but a single claw-bearing finger instead of three such as in the Ostrich, while the absence of the ornamental wing-plumes and for that matter, of tail-plumes as well serves to further distinguish them. They have very strong legs and feet with three toes, the hallux or hind toe being absent, while the three front toes are provided with claws and have the middle phalanges somewhat shortened. The plumage is quite hair-like in appearance and somewhat harsh to the touch.
The Casuariiformes embrace two families, the Dromaeidae, or Emeus, and the Casuariidae, or Cassowaries, each with a single living genus.’ The Emeus are distinguished by their larger size, a feathered neck and head, by a broad bill, and the absence of a casque or helmet on the head. The bill has the culmen at the base elevated and sloping to the tip, which overlaps that of the lower mandible; the oblong-oval nostrils are placed in a large membranous groove. The wings are entirely without remiges and the tail is not apparent, while the toes are unequal, the inner one being the shorter, and provided with strong, obtuse claws.
The second family (Casuariidae) is distinguished by the smaller size, a long compressed and keeled bill, with the suboval nostrils in the middle of a broad membranous groove, while the head is ornamented by an elaborate bony helmet. The head and neck are destitute of feathers, the skin being brightly colored in life and the neck wattled. The wing bears about five long, stiff, rounded, webless quills, and the inner of the rather long toes is provided with a very long, powerful claw, the claws of the other toes being of moderate size, curved and obtuse.