Page:Popular Science Monthly Volume 46.djvu/782

762 Technically, the common African ostrich is known as Struthio camelus, and so the ostrichlike birds, as a group, have come to be spoken of as the "struthious types," or those with "struthious characters." Again, the group as a whole has been designated as the Ratitæ, which primarily has reference to the fact that the breastbone or sternum in any one of them lacks a keel, and so is "raftlike" as compared with a sternum possessing the character.

With but one or two exceptions, all the rest of existing birds have a more or less well-developed median keel on their sterna, and as the Carinatæ they form the second great division of the class Aves. Carina is the Latin word meaning "a keel," hence the name for the group. To this keel are attached the pectoral muscles, which are so essential to the power of flight.

Linking together the ratite and carinate avian groups, we have an interesting subgroup of birds known as the tinamous. In 1827 L'Herminier thought that the nearest kin of the tinamous among the carinate birds were the rails (Rallidæ). They are South American and Mexican types, and about fifty species of them are known, and systematists have consigned these to some nine or ten genera. All these forms have a general external resemblance to each other, and, as many observers have noted, to those birds we call "partridges." The largest tinamous are about the size of our "prairie chickens," and the smallest about the size of the least of our "quails." They are fine eating; fly pretty well, but are foolish and easily captured. Some of them have but three toes on either foot, others four, and all lay wonderfully handsome eggs. These latter may be of various shades of green, blue, pink, or orange, varying with the species, but in all they have highly burnished shells resembling porcelain or brilliantly polished metal. Little is as yet known of their habits.

Sharpe speaks of the tinamous as "struthious partridges," and Hudson claims that some of their "habits are thoroughly partridgelike," and if they lead in the direction of the gallinaceous