160 A NATURALIST IN THE PACIFIC CHAP. 



for their fracture require a blow with a hammer. The implication is 

 that the extinct Columbae were able to transport to oceanic groups 

 seeds and " stones " which no existing pigeon could now carry over 

 a tract of ocean. I am inclined to extend this view also to extinct 

 Struthious birds, and to suppose that they were able, like the casso- 

 wary (see page 1 52), to fly across tracts of sea in ages gone by. Though 

 such an agency would come under discussion in connection with 

 the floras of New Zealand and Madagascar, we have no evidence 

 to show that birds of this family ever reached the tropical islands 

 of the open Pacific. 



The Megapodidae of the Western Pacific are a family of birds 

 that suggest themselves in this connection. Their distribution 

 corresponds with that of Pandanus in the Western Pacific, except- 

 ing the littoral species ; and like Pandanus the Megapodes have 

 41 differentiated " in every group. The limited powers of flight 

 possessed by existing species would unfit them for crossing wide 

 tracts of sea ; but the parent form or forms of all these species 

 must have been able to traverse broad tracts of ocean. These 

 birds subsist on fallen fruits, seeds, &c. ; but I have no data 

 relating to them as seed-dispersers. 



It is evident from the endemic character of most of the species 

 of Pandanus in oceanic islands that, except with a few widely-spread 

 littoral species, the dispersal of the genus has been for ages 

 suspended. Whether the explanation is to be found in the isola- 

 tion and differentiation of the extinct Columbae of the Mascarene 

 Islands, where the endemic species of Pandanus are most numerous, 

 has yet to be established. It seems to offer the only way out of 

 the difficulty, unless we accept the old view concerned with the 

 continent of Lemuria. 



BARRINGTONIA. 



There are two littoral species of this genus in the Pacific, 

 B. speciosa and B. racemosa, both widely spread over the Old 

 World, but only the first is generally distributed over the Polynesian 

 region reaching east to Ducie Island, whilst the second does not 

 extend east of Fiji and Samoa. With the exception of one or two 

 inland species in Fiji and Samoa no inland species have been 

 recorded from the groups of the open Pacific, and the genus is not 

 represented at all in Hawaii. If it were not for a suspicion that the 

 aborigines may have aided in the distribution of the inland species, 

 the advocate of the previous continental connections of the islands 



