298 A NATURALIST IN THE PACIFIC chap. 



across oceans that we are at present acquainted with. The two 

 first-named genera occur in South America as well as in the 

 Australo-Polynesian region, some of the species in these two 

 regions, though the Pacific Ocean divides them, being closely 

 related. Dammara is, on the other hand, confined to a much more 

 limited area, extending from New Zealand to Borneo. It is from 

 the distribution of this genus that the continental theory derives its 

 chief support 



Yet it may be remarked that something more than questions 

 relating to the capacity for dispersal are involved here. This is at 

 once indicated by the circumstance that although Podocarpus is 

 known to be dispersed by frugivorous birds, it is not found in 

 Polynesia east of Tonga, and the same may be said of Dacrydium, 

 which does not occur east of Fiji. In this connection it is 

 necessary to notice the intrusion of Araucaria into the tropical 

 Pacific from Eastern Australia to New Caledonia and the New 

 Hebrides. The fact of this genus not having been recorded from 

 Fiji or any of the groups east of the New Hebrides is very 

 remarkable, and scarcely in accordance with the continental 

 hypothesis. There is a persistence in type of these genera of the 

 Coniferae during geological time that prevents us from dealing with 

 them on the lines that are required by the mass of the flowering- 

 plants. Other factors intervene, and we apply with hesitation the 

 same canons of dispersal that we employ for the general bulk of 

 the plants of the Pacific islands. If, as often happens, a specific 

 distinction alone separates the Conifers of the same genus on 

 either side of the Pacific Ocean, it must possess in point of 

 time a very different value from that which we would usually 

 attach to specific distinctions in the floras of the Pacific islands. 



Dammara (AGATHIS). — The Dammara region includes 

 Eastern Australia, New Zealand, New Caledonia, with the New 

 Hebrides, Fijian, and Santa Cruz groups, and extends north-west 

 to Java and Borneo. Only ten species are named in the Index 

 Kewensis, and of these four are assigned to New Caledonia and 

 two to Fiji, the focus of geographical distribution being, therefore, 

 as Seemann long since pointed out, in the islands of the Western 

 Pacific. The absence of the genus from the neighbouring Samoan 

 and Tongan groups is very significant ; and it is evident that the 

 ordinary agencies of dispersal, whether birds, winds, or currents, 

 have here failed to extend the genus over a few hundred miles 

 of sea. 



When by means of observation and experiment we turn to the 



