Apteryx, a genus of Ratite birds, constituting a family (Apterygidae), with four species (or perhaps two species, each consisting of two races), all from New Zealand. These birds, called by the Maoris "Kiwi," or "Kiwi-Kiwi," from their cry, have the merest rudiments of wings, and these are so hidden that they appear to be altogether wanting; the plumage is much more like hair than feathers, and there is no aftershaft. The North Island Kiwi (A. mantelli) and the large Grey Kiwi (A. haasti) are represented in the South Island by A. australis and the Little Grey Kiwi (A. oweni). As is evident from the popular names, the plumage of two of these species is grey; that of the North Island Kiwi is rufous brown, and that of A. australis sandy or greyish brown. The smaller species are about the size of a domestic fowl, but the Large Grey Kiwi is about two feet in height. The form of the body is not unlike that of the penguin, set on short stout legs, with three toes in front, and a short one behind raised above the level of the rest. The neck is short and thick, and the head is furnished with a long smooth, slender bill, having the nostrils at the tip. The bill is driven into the ground in search of worms, which constitute the principal food of these birds. Little is known of their habits in a state of nature beyond the fact that they live in pairs and pass the day in holes in the ground or at the foot of trees, coming out in the twilight to feed. They run with great rapidity, and if attacked endeavour to escape, but if hard pressed they raise the foot and strike downwards with considerable force, thus using the sharp and powerful claws as weapons of defence. Many living specimens have been brought to Europe, and they bear confinement fairly well. The North Island Kiwi in the Zoological Gardens, Regent's Park, laid two eggs, disproportionately large for the size of the bird, which were incubated for some time, but without results.