BIRDS

cialized vertebrate bipeds of worldwide distrib ution, charac terize d by their intense metabolism, indicated by high body temperature, by numerous anatomical adaptations for the function of flight, by the po e ion of feathers, and by the hatching of their young from eggs with calcareous shells, The extinct Arch Alopteryx forms the sub-cla Archzornithes or Saurure. All other birds are included in the sub-cla Neornithes. The first division of the latter, Ratitze, running birds without power of flight, persisting since the Miocene, with keelle breastbone, are represented by the ostrich (Struthio) of Africa and Arabia, the 8S. Amer. ostrich (Rhea), the AusMalayan ca owaries (Casuarius), the little wingle and four-toed kiwi (Apteryx) of New Zealand and its extinct giant relative, the moa (Dinornis), the recently extinct order Mpyornis of Madagascar, and various Eocene and Pleistocene species. The second division, Odontolcz, consists of extinct swimming birds with keelle breastbone and teeth situated in grooves, and a few affinities to iiving flying types. Hes per ornis of N. America and Enaliornis of English cretaceous strata are the typical representatives. The flying birds with keeled breastbone are comprised in the third division, Carinate. Their principal adaptations for flight are the general shape of the body, offering comparatively little resistance to the air; the construction of the wings; the keeled breastbone for the attachment of the powerful pectoral muscles; the air-spaces in the body cavity and in the long bones in connection with the non-expansible lungs, and the air in spongy spaces in the skull bones connected with the Eustachian and nasal tubes, facilitating breathing during flight. Many birds undertake long and hazardous migratory flights to ensure a supply of food when the climatic conditions make a sojourn in the breeding area prohibitive. The remarkable development of the brain, manifesting itself in the complex emotions of courtship, and all the functions a ociated with the care of offspring (e.g., nest building), and in migration and other habits, makes some orders of the Carinate rank with the mammals, and thus with the highest evolutionary phases of the animal kingdom.: A segregation of Car in a tee, over 11,000 species into 14 orders, introduced by Dr. Gadow, seems most advantageous. The extinct (cretaceous) Ichtyornithes have biconcave vertebre and teeth in sockets, and were able to fly well. The aquatic Colymbiformes with straight bill include the grebes and divers. In the penguins, or Sphenisciformes, the wings are transformed into flippers for swimming. Flying seabirds like albatro es and petrels belong to the order ants, frigate-birds, and pelicans, however, as well as wading birds like storks, i fbises, and flamingos, are grouped as} and swans are included in An ser i formes. The Falcon i formes are diurnal birds of prey and excellent fliers, and include and others. Of the small Central and 8. Amer. order Tin am i formes, the tinamou, a partridge-like game-bird, is the best known representative. Fowls, pheasants, quails, and similar birds constitute the order Gall i formes, with the curious hoatzin of Northern S. Amer., whose unhatched chick has clawed fore-limbs, showing reptilian affinities. Wading birds, like cranes, rails, bustards, and bitterns, are Gruiformes. The large order Charadriiformes includes such different types as plovers, pigeons, auks, d the extinct dodo of birds belong to the Cuculiformes. <A large order with most varied representatives is the Coraciiformes, comprising woodpeckers, kingfishers, and others. The most heterogeneous order of all is the Pa er i formes, in some of which the emotional life finds its most highly developed and beautiful expre ion; it includes the birds of paradise, bower, weaver, and tailor birds, and all the singing birds like finches, thrushes, nightingales, etc.