BIRDS OF NORTH AND MIDDLE AMERICA. 547 
Adult male.—Wing, 261.5-273 (268.1); tail, 139-148 (144); 
exposed culmen, 41-44.5 (48.4); tarsus, 23.5-25.5 (24.4); middle toe, 
31-82.5 (31.5).4 
Adult female.—Wing, 259-266 (263.3); tail, 137.5-140 (138.2); 
exposed culmen, 39.5-42. (40.5); tarsus, 23-24.5 (23.6); middle toe, 
29-31 (30).? 
Atlantic Ocean, chiefly on American side, from Florida Keys, 
Bahamas, and coast of Louisiana (where resident), southward through 
West Indies and along Gulf and Caribbean coasts of Mexico and 
Central America to islands of Trinidad and Los Hermanos, coast of 
Brazil, St. Paul Rocks, mid-Atlantic, Fernando Noronha, and south 
Trinidad, off Brazil, and St. Helena, Ascension, and Tristan da 
Cunha and Inaccessible islands, off southern Africa; breeding through- 
@ Hight specimens. » Five specimens. 
Ex- . 
Locality. Wing. | Tail. | P98°4 | parsus.| Middle 
men. 
MALES. ” 
One adult male from Bahamas............-.2-.22.-222-00--+-+ 265 139 41.5 24 31 
Four adult males from Porto Rico...............2-22-2-------- 270.2 | 143.7 44.1 24.3 31.5 
One adult male from Grenada. ....... 269 146 44.5 25 32 
One adult male from Atlantic Ocean e --| 261.5] 148 BE Nheceseud|senaceee 
One adult male from Tepic (Isabella Island) (A. s. ridgwayi)...| 261.5 | 149.5 41 25.5 30 
Four adult males from coast of Guerrero (A. s. ridgwayi)....... 266.2 | 147.7 42.9 24.2 30.6 
Two adult males from Clipperton Island (A. s. ridgwayi).....-. 274.5 | 161.5 40.5 24.5 32.2 
Two adult males from Cocos Island (A. 8. ridgwayi)........-..- 289 165.5 41.7 25 32.5 
Seventeen adult males from Galapagos Islands (A. s. galapa- 
QENSIS) w wiacnccarcraas ean cutivcteresmnrmecececncmemeaeceaaaaasiarsins 270 151.3 39.8 22.9 30.8 
One adult male from Guam, Pacific Ocean (A. s. unicolor?)....| 283 167 40 26 33.5 
One adult male from Raraka Island, Pacific Ocean (A. s. uni- 
GCOLOT coe aeciencyeieiec ecmenwide seein mace SeSeeen em aecemee mas 284.5 | 167.5 44.5 26 33 
Three adult males fromislands near Madagascar (A.s.rowsseaui)| 277.7 | 151 42.8 24.8 31.2 
One adult male from Straits of Malacca (A. s. pileatus?)....... 275 . 154 40 23.5 30. 5 
One adult male from southern China Sea (A. s. pileatus)....... 265 169 38 25.5 31.5 
FEMALES. ; 
One adult female from Tortugas, Florida.........-....-...---. 261.5 | 136 BOE HW eccssssceeeacecacuchs: 
Four adult females from Porto Rico.......-......2--+2-2-0-2+- 263.7 | 121.7 40.6 23.6 30 
One adult female from British Honduras...............-.--.-- 272 151 43.5 24 31 
Eight adult females from Tepic (Isabella Island) (A. s. ridg- 
DOG Dotnet nc mainte aceienk aeireeweltaminnwnccadmuincte 274.6 | 151.1 41.6 24.4 30.7 
Four adult females from coast of Guerrero (4.8. ridgwayi)..... 272.5 | 147 41.1 24 30.7 
Sixadult females from Clipperton Island (A. s. ridgwayi)...... 270 153. 8 39.6 24.1 31.2 
Fight adult females from Galapagos Islands (A.s. galapagensis).| 265.2 | 144.7 38.9 22.6 30 
One adult female from Laysan Island (A. s. unicolor?)......... 277 166 40 24 30 
One adult female from Guam, Pacific Ocean (A. s. wnicolor?)..| 278 164.5 39 23 30 
One adult female from Seychelles (A. 8, TOUSSEMUI).....-2----- 244 144 41 23 31 
Two adult females from southern China Sea (A. s. pileatus)....| 270 150 ~ 37.7 24.5 31.2 
