50 ZOOLOGICAL GARDENS. 



regarded as the representative of the family in Europe. 

 Some species, however, belonging to the same group 

 with this latter bird, extend themselves over a consider- 

 able portion both of Africa and Asia. 



The principal external characters by which the birds 

 above enumerated are connected together, consist in the 

 absence of the hind-toe, of which not even a vestige 

 remains ; in the length and power of their legs, which 

 are completely bare of feathers ; in the shortness of 

 their wings, and their uselessness as organs of flight ; 

 in the length of their necks ; and in their strong, blunt, 

 flattened bills. The plumes of the more typical among 

 them are distinguished by the want of cohesion between 

 their barbs, a cohesion which in other birds is mani- 

 festly subservient to the purposes of flight, and which 

 would therefore have been superfluous in these, which 

 never raise themselves above the surface of the ground. 

 Their food is almost entirely vegetable, and consists of 

 seeds and fruits, or, rarely, of eggs and worms. Between 

 the crop, which is of enormous size, and the gizzard, 

 which varies in thickness and power, several of them 

 are furnished with an additional ventricle, analogous 

 to the structure which prevails in Ruminating Quadru- 

 peds. They occupy a station in some degree inter- 

 mediate between the Rasorial Birds and the Waders, 

 approaching the latter in many particulars of their 

 outward form, but much more closely connected with 

 the former in their internal structure, in their food, 

 and in their habits. 



Of the differential characters which give to the 

 Ostrich the rank of a genus, the most important is 

 founded on the structure of its feet, which have only 

 two toes, both directed forwards and connected at their 

 base by a strong membrane ; the internal beincr consi- 

 derably larger than the external, and being furnished 



