98 
EDWARD A. WILSON. 
white and five dark, and in the average of the bill and wing measurements given below 
the advantage in size is always slightly with the white variety. 
a Gag Bq 3 3 
_ | o, | #2 | 2s | ea | axe 
gq Ag Se Ba So9 Bo 8 
Ss a gas Cg Bad 23¢ 
% 3 RES] Bo ae 3 8 
e ee Zag Pe Sea | $38 
3 fee | g@ | B85 | Ese 
a Es & 
WuHitrt Brrps— 
M.t, g 54°7 5°83 10°2 2°5 15 7:6 
D. 24, g 53°38 5°83 10°5 2°7 1°5 7°8 
D. 28, ¢ 54°7 5°38 10°1 24 15 ‘dans 
D. 22, g 54:7 5°83 10°38 2°6 15 77 
Average 54°35 5°83 10°275 2°55 15 °F 
DaRKER Brrps— 
M. No. 29, dark, 9 ... 53°38 4:5 9°3 2°4 1°3 74 
D. 20, white head, ? 53°38 4e4 8°7 2°4 1°3 7°0 
D. 21, mottled grey, g 52°1 4-4 8-7 2°4 1°3 6°9 
Byiss 4 » 8 53°83 Ard 8°8 2-4 1:2 7°0 
M. w, dark, ? 521 5°38 10°1 2°6 1°6 8:0 
Average 52°82 4°6 9°12 2°44 1°34 7°26 
This, one might think, could hardly have been accidental, but as three of the 
darker specimens were females, and all the white were males, the figures were not 
conclusive, and continuing the measurements to include birds in the collections of ‘the 
British Museum, as the following table shows, the advantage in size is found to be 
not invariably with the white variety :— 
Wuitrt Brrps— 
93.12.4.2 Snares ... “i 
01.1.7.29 Campbell Islands 
DarKER BIRDS— 
92.2.10.401 black... 
03.12.30.208 v. dark ? 
80.8.3.5 black g ... 
80.11.18.635 v. dark 
Wing, cm. 
50°8 
53°4 
49°5 
47°0 
51°5 
52°1 
4 Zag A = oc Ss 
El gq. | BS Seq | ds 
42q HB a2 ago Do 8 
a Oo ae os 23 ogg 
os By pa ages = 8 
as gos ag in| gah 
bE ABS a) 833 234 
3 dom 5% gan ile 
r aoe 5% 5 b 
4°5 8°9 2°3 1°3 6°9 
5:4 10°0 2°6 14 77 
4°3 82 2°71 1:2 6:2 
4°7 9°0 2°0 1°3 7-2 
58 9°8 2°6 1:4 7-9 
5°0 10°2 2°5 14 8:1 
