5 I 2 MANUAL OF ZOOLOGY. 



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. 221, B) is destitute 

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

 muscles are attached (hence the name of Ralita, 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 num- 

 ber, 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. 221. Cursores. A, Foot of the Ostrich (Strnthio camehts) ; B, Sternum of 

 the Emeu {Dromaius Novce-Hollandice). 



The order Cursores may be divided into the t\vo families of 

 the Struthionidcz and the Apterygidce the former characterised 

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

 Rhea, Emeu, and Cassowary,* with several extinct forms ; the 

 latter comprising only the Apteryx of New Zealand, and char- 

 acterised by the possession of a rudimentary hallux. 



The African Ostrich (Struthio camelus) occurs in the desert 

 plains of Africa and Arabia, and is the largest of all living 

 birds, attaining a height of from six to eight feet. The head 

 and neck are nearly naked, and the quill-feathers of the wings 

 and tail have their barbs wholly disconnected, constituting the 

 ostrich-plumes of commerce. The legs are extremely strong, 

 and are terminated by two toes only (fig. 221, A), these con- 

 sisting respectively of four and five phalanges, showing that it 

 is the hallux and the innermost toe which are wanting. The 



