CURSORES AND RASORES. 451 



CHAPTER LXVIII. 



CURSORES AND RASORES. 



ORDER III. CURSORES. The third order of Birds is that 01 

 the Cursores, or Runners, comprising the Ostriches, Rheas, 

 Cassowaries, Emeus, and the singular Apteryx of New Zealand. 

 In many respects the Cursores are to be looked upon as an 

 artificial assemblage ; but in the meanwhile it will be most 

 convenient to consider them as forming a distinct division. 

 The Cursores are characterised by the rudimentary condition 

 of the wings, which are so short as to be useless for flight, and 

 by the compensating length and strength of the legs. In 

 accordance with this condition of the limbs, many of the bones 

 retain their marrow, and the sternum (fig. 175, B) is destitute 

 of the prominent ridge or keel, to which the great pectoral 

 muscles are attached (hence the name of Ratita, applied by 

 Huxley to the order). In the Ostrich the pubic bones of the 

 pelvis unite to form a symphysis pubis, as they do in no other 

 bird, and in all the pelvic arch possesses unusual strength and 

 stability. The legs are extremely robust and powerful, and the 

 hind-toe is entirely wanting, except in the Apteryx, in which it 

 is rudimentary. The anterior toes are two or three in number, 

 and are provided with strong blunt claws or nails. The plumage 

 presents the remarkable peculiarity that the barbs of the 

 feathers, instead of being connected to one another by hooked 

 barbules, as is usually the case, are remote and disconnected 

 from one another, presenting some resemblance to hairs. 



Fig. 175. Cursores. A, Foot of the Ostrich (Struthio cantelus) ; B, Sternum of 

 the Emeu (Dromaius Novce-Hollandice). 



The order Cursores may be divided into the two families of 

 the Struthionidcz and the Apterygidce the former characterised 

 by the absence of the hallux, and comprising the Ostrich, 



