4 PROCEEDINGS OIT THE 



Now, if the endemic genera of islands be in reality survivals — 

 the current view — one would expect that they would at least 

 show a tendency to belong to families that are small or of broken 

 distribution, i.e. such families as we have been accustomed to 

 look upon as more or less moribund. And in any case, one 

 would not expect the great bulk of them to belong to the large 

 and " successful " families. 



If, on the other hand, age and area hold good (including the 

 extended deduction above given), then the endemic genera should 

 be found to occur on islands in proportions not dissimilar to the 

 proportionate sizes of existing families. And further, as on this 

 view the larger families are in general the older in their aflinity 

 circles, we shall expect tliein to be rather better represented 

 (proportionately) than the smaller. 



In order to test this question thoroughly, I have added up all 

 the endemic genera of all the islands in the world, and for com- 

 parison also tiiose (1) of West Australia, South Africa, and Brazil 

 (the mainland ai'eas richest in endemics) ; (2) of Australia, Africa, 

 and South America ; and (3) of the "World. Examination of the 

 tables thus obtained soon shows that if one take the families in 

 groups of ten in order according to the number of genera they 

 contain in the world (i.e. beginning with Compbsitae and ending 

 with monotypic families), the proportion of island genera to .the 

 total is closely the same throughout the list, and the same holds 

 for all the four areas mentioned. Thus the first ten families 

 contain 40*1 per cent, of the genera of the world, 39-4 per cent, 

 of tiiose of Australia, Africa, and South America, 40'5 per cent, 

 of those of West Australia, etc., and 38*3 per cent. (606 genera 

 out of 1582) of the endemic genera of islands. And the approxi- 

 mation is equally close all down the scale, so that the curves 

 jH'oduced almost coincide. 



Comparison shows with equal clearness that the proportional 

 representation among the endemic genera of islands decreases as 

 one goes down the scale. The first 100 families in the world 

 have island endemic genera in 02, the genera being 12'9 per cent, 

 of the total genera in the families. The intermediate 92 families 

 are represented by 45 only, with 9-28 per cent, of their genera, 

 and the last 100 by 13 with 8*72 per cent. 



The second prophecy made above is thus fully borne out by 

 the facts. Various pieces of confirmatory evidence are also given. 



A discussion ensued in \\hich the undermentioned took part : — 

 Dr. A. B. liendle, F.R.S., Se.-.L.S., Lt.-Col. J. H. TuU Walsh, 

 Dr. 11. U. Gates, and Mr. C. C. Ijacaita, the author replying. 



December 9th, 1920. 



Dr. A. S-MiTn AVoodwaud, F.R.S., President, 

 in the Chair. 



The Minutes of the General Meeting of the 18th November, 

 1920, were read and confirmed. 



