762 THE POPULAR SCIENCE MONTHLY. 



Technically, the common African ostrich is known as SirutJiio 

 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 Ratitm, 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 CarinatcB 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 mus- 

 cles, 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.f 

 In 1827 L'Herminier thought that the nearest kin of the tina- 

 naous among the carinate birds were the rails (Rallidcp). 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. 



Sliarpe speaks of the tinamous as " struthious partridges," and 

 Hudson claims that some of their " habits are thoroughly par- 

 tridgelike," I and if they lead in the direction of the gallinaceous 



India, which are also of birds which were of this group. All of these, both existing and 

 fossil, arc or were flightless birds, and the African ostrich, no doubt, the most specialized of 

 any of them. According to Cope, there was a gigantic ostrichlike bird that lived in Texas 

 and New Mexico during the Eocene time {Diatriima). It was double tbe size of an ordi- 

 nary ostrich. The largest moa, Dinornis giganieus, was nearly ten feet high. 



* It is probable that all tlie early ancestors of liirds were flightless, and consequently 

 all had kccllass sterna, except such forms as IcJdhiiofnis, and, no doubt, its predecessors were 

 ratite birds, in the sense that they had non-carinate breastbones. 



f These birds have deep keels to their sterna, but at the same time possess so many 

 struthious characters in their organizations that they have been designated by Huxley as 

 the Dromaiognnthie the genus Droiiueus containing the emeu and emeus and tinamous 

 have the structure of the palate much the same. 



X Nowadays most scientists refer to the tinamous as the Cn/phiri, from the fact that 

 their tails are concealed by the coverts (Gr. krupio, I conceal, and oura, the tail). 



