214 
Willis.—Age and Area. 
and Area these would probably prove to be mainly among those recorded 
as possessing an unusually low degree of rarity (for endemics), and I asked 
for a list, which Mr. Gamble has kindly furnished. The species so far 
recorded are: 
Dillenia retusa 
Uvaria meteropoda 
Xylopia parvifolia 
Alp house a sclerocarpa 
Garcinia echinocarpa 
Calophyllu m tr apezifolin m 
Erythroxylon obtusifolium 
Olax zeylanica 
Microtropis Wallichiana 
Vitis glyptocarpa 
Sapindus erectus 
Crotalaria Walkeri 
Eugenia Fergusoni 
Eugenia olivifolia 
Osbeckia buxifolia 
Osbeckia rubicunda 
Casearia coriacea 
Elcracleum zeylanicum 
Hedyotis Lessertiana 
Urophyllum zeylanicum 
Ixora Thwaitesii 
Emilia zeylanica 
If one note, from Trimen’s * Flora’, the recorded rarity of each of these 
in Ceylon, one finds that of the 22, there are VC i, C 4, RC 11 (i. e. 16 
below average rarity), RR 3, R 2, VR 1 (i. e. 6 above average rarity). The 
22 species show an average rarity of (22/70) 3*18, much below the average 
for Ceylon endemics of 4*34. Their removal alters this to (787/3,448) 4-38. 
As only one place of decimals was employed in my calculations, it will be 
seen that the figures remain unaltered—a fact which may help to impress 
upon some objectors how little difference in the statistics is made by the 
alteration of a few individual figures. Incidentally, by removing 11 from 
the old list of 139 RC, and only 3 from the 136 RR, the change removes 
the only break in the regularity of my figures which has so far shown itself 
when dealing with considerable numbers. 
Summary. 
This paper is chiefly concerned with a reply to the criticisms upon Age 
and Area that were made at the Hull meeting of the British Association, 
and special attention is once more directed to the most fruitful sources of 
difficulty, for little new criticism was brought up. People insist upon 
applying Age and Area to individual cases, or to unrelated forms, and in 
both instances, as has frequently been pointed out, this will only lead to 
error and difficulty* The law is only applicable to groups of at least ten 
allied forms. The other great difficulty is the view that endemic forms are 
chiefly relics, yet, though the latter are common enough, it is not properly 
realized that they are quite lost in the crowd when large numbers are con¬ 
sidered. 
Several original pieces of work are then inserted to illustrate what has 
been said. A definite reply is made to the criticism of Mr. Tate Regan, 
who was the leader of the opposition at Hull, and who made several 
animadversions upon Age and Area that do not seem to me to be justified. 
Incidentally a brief analysis of Guppy’s work upon distribution of family 
