Ipswich Museum. 149 



F 



^B uniting Asia with Africa, the progeny of the primary pair created or 

 ^K Uberated at the hypothetical centre might have travelled to the latter 

 ^m continent, and there have propagated and dispersed themselves south- 

 ^B ward to the Cape of Good Hope. It is remarkable, however, that 

 ^K the Ostrich should not have migrated eastward over the vast plains 

 ^B or steppes which extend along the warmer temperate zone of Asia, or 

 ^B have reached the southern tropical regions ; it is in fact scarcely 

 ^B known in the Asiatic continent, being restricted to the Arabian De- 

 ^B serts, and being rare even in those parts which are most contiguous 

 ^B to what we may call its proper continent — Africa. If we next con- 

 ^B sider the locality of the Cassowary, we find great difficulty in con- 

 ^B • ceiving how such a bird could have migrated to the islands of Java, 

 ^B the Moluccas, or New Guinea, from the continent of Asia. The 

 ^f Cassowary is not web-footed like the swimming birds ; for wings it 

 has only a few short and strong quills, flow could it have overcome 

 the obstacles which some hundreds of miles of ocean would present 

 to its passage from the continent of Asia to those islands ; and 

 furthermore, how is it that no individuals have remained in the 

 warm tropical southern border of Asia, where the vegetable suste- 

 nance of the Cassowary seems as abundantly developed as in the 

 islands to which this wingless bird is now exclusively confined ? If 

 the difficulty already be felt to be great in regard to the insular posi- 

 tion of the Cassowary, it is still greater when we come to apply 

 the hypothesis of dispersion from a single centre to the Dodo of the 

 island of Mauritius, or the Solitaire of the island of Rodriguez. How, 

 again, could the Emeu have overcome the natural obstacles to the 

 migration of a wingless terrestrial bird from Asia to Australia ? and 

 why should not the great continent of Asia have offered in its fertile 

 plains a locality suited to its existence, if it ever at any period had 

 existed on that continent ? A bird of the nature of the Emeu was 

 hardly less likely to have escaped the notice of naturalist travellers 

 than the Ostrich itself ; but save in the Arabian Deserts, the Ostrich 

 has not been found in any part of Asia, and no other species of 

 wingless bird has ever been met with on that continent : the evidence 

 in regard to such large and conspicuous birds was conclusive as to 

 that fact. In order that the Rhea, or three-toed Ostrich, should reach 

 South America, by travelling along that element on which alone it is 

 organized and adapted to make progress, it must, on the hypothesis 

 of dispersion from a single Asiatic centre, have travelled northward 

 into the inhospitable wilds of Siberia : it must have braved and over- 

 come the severer regions of the arctic zone : it must have maintained 

 its life with strength adequate to the extraordinary power of walking 

 and running over more than a thousand miles of land or frozen ocean 

 utterly devoid of the vegetables that now constitute its food, before 

 it could gain the northern division of America, to the southern divi- 

 sion of which it is at present, and seems ever to have been, confined. 

 The migration in this case could not have been gradual, and accom- 

 plished by successive generations. No individual of the large 

 vegetable-feeding wingless bird that now subsists in South America 

 could have maintained its existence, much less hatched its eggs, in 



