ZOOLOGICAL ZONES 1525 



island of Madagascar. The egg of this bird, which 

 may have suggested to the Arabian voyagers, attain- 

 ing Madagascar from the Red Sea, the idea of the 

 Roc of their romances, would hold the contents of 

 six eggs of the ostrich, sixteen eggs of the cassowary, 

 and one hundred and forty-eight eggs of the common 

 fowl. 



Had all the terrestrial animals that now exist 

 diverged from one common centre within the limited 

 period of a few thousand years, it might have been 

 expected that the remoteness of their actual local- 

 ities from such ideal centre would bear a certain 

 ratio with their respective powers of locomotion. 

 With regard to the class of birds, one might have 

 expected to find that those which were deprived of 

 the power of flight, and were adapted to subsist on 

 the vegetation of a warm or temperate latitude, 

 would still be met with more or less associated to- 

 gether, and least distant from the original centre of 

 dispersion situated in such a latitude. But what is 

 the fact? The species of no one order of birds is 

 more widely dispersed over the earth than the wing- 

 less or struthidus kind. Assuming that the original 

 centre has been somewhere in the southwestern 

 mountain range of Asia, there is but one of the spe- 

 cies of flightless birds whose habitat can be recon- 

 ciled with the hypothesis. By the neck of land still 

 uniting Asia with Africa, the progeny of the pri- 

 mary pair created or liberated at the hypothetical 

 centre might have traveled to the latter continent, 

 and there have propagated and dispersed themselves 

 southward to the Cape of Good Hope. It is remark- 



