405 
relationship that the Andaman-Nicohar chain hears to Indo-China and 
the Malay Archipelago, and perhaps neither it nor the Andamans ought 
to be spoken of as physiographically a part either of Indo-China or 
of Malaya;* these 20 species cannot therefore be cited as indicating 
either an Indo-Chinese or a Malayan influence. The purely Indian 
Sterculia villosa must obviously be similaidy excluded ; there are therefore 
21 species, or 32 per cent, of this group, that afford no evidence either 
way. 
Of the remaining species, one-half, i. e., 23 species, or 35 per cent, 
of the whole, occur both in Indo-China and Malaya ; these also give no 
evidence as regards this question. Of the other 23, 15 extend from 
Indo-China to these islands (some of them, like Dendrocalamus strictus, 
not going further than the Coco Group), without extending to Malaya; 
while only 8 extend from Malaya to these islands without occurring in 
Indo-China. The ‘‘remanent” species, therefore, so far as this evidence 
goes, indicate the predominance of an. Indo-Chinese element, a fact 
that is altogether in accordance with wdiat we should expect from our 
knowledge of the configuration of the sea-bottom along the line of islands 
fi-om Cape Negrais in Arracan'to the Nias Islands and Sumatra. 
Reviewing the results of the preceding paragraphs we conclude that 
288 species, or 80 per cent, of the flora, may conceivably have been in¬ 
troduced : 33 species, or 9 per cent., by human agency ; 94 species, or 
28 per cent., by birds ; 60 species, or 17 per cent., by winds and JOl 
species, or 28 per cent., by the sea. We find moreover that the evidence 
is in favour of the bird-introduced species having, so far as those 
brought by wading- and water-birds are concerned, been introduced 
from the north, and so far as those brought by frugivorous and by seed¬ 
er grain-eating birds are concerned, having come in almost equal numbers 
from Malaya or the Andamans to the south, and from Indo-China to 
the north. So far as wind-introduced species are concerned the influence 
of the north-east monsoon is apparently the more active ; so far as the 
sea-introduced species are concerned the influence of currents from 
Malayan seas to the south-east has been paramount. 
The subjoined table gives a synoptic view of the probable origin 
of the Coco Island flora. 
* The writer has proposed the name “ Malay Isthmus ” for-the conjoint area 
that includes Tenasserim, the Andamans and the Nicobars, and believes that it will 
be found convenient to recognise this as a distinct phytogeographical subdistrict. See 
Ann. Boy. Bot. Garden, Calcutta, iii, 238. 
215 
