150 CALIFORNIA ACADEMY OF SCIENCES [Proc. 47H Ser. 
MEASUREMENTS (in millimeters) 
Upper Mandible Middle 
No. Sex | Length | Extent | Wing | Tail | Culmen)-—————————_| Tarsus |Toe and 
Depth | Width Claw 
9293 460 | 985 | 296 | 126 | 40.4 | 10.4 | 13.4 | 47.6} 61 
9295 | 465 980 | 297 | 132 | 40.4 | 10 13.6 | 50.1 | 61 
LIS (GW Pig ero Pe aisecia its ak 285 | 123 | 43.1 | 10.6 | 13.5 | 49 58.9 
a My S isto MOCodN  Gixse s ooarae 298 | 130 | 42.7 | 10.7 | 14.2 | 49.8 | 63.2 
16233 | & 493 | 1016 | 297 | 125 | 43.5 | 11 ISL) |) Ou 63.7 
HOPSIEY | Cpl heroes o allaoa.ore 6 291 | 120 | 43 11.2 | 14.6 | 51 63.1 
1868211 of 483 991 | 298 | 129 | 43 11.2 | 15 48.9 | 61 
186831, o& 483 | 991 | 299 | 129 | 42.1 | 11 15.4 | 49.5 | 62.8 
186841] of 483 | 1016 | 309 | 127 | 45 11.1} 14.2 | 50 63.1 
186851] of 483 | 1016 | 307 | 133 | 42 10.6 | 15 48.9 | 62.8 
186864 of 476 991 | 291 | 126 | 41.9 | 10.8 | 13.5 | 48 62.1 
7A. Gil liso ee alloos coe 297 | 135 | 42.5 | 9.9 | 13.2 | 48 61 
9294 | 9 AOS A OTS eee ees 119 | 41.5 | 10.1 | 14.5 | 48.1 | 61.9 
16234 | 9 470 | 991 | 293 | 125 | 40.7 | 10 13.7 | 50.3 | 62.8 
LOZ Ope OM orem sralts aereue: 303 | 137 | 43.1 | 10.6 | 14.5 | 49.5 | 61.7 
Halocyptena microsoma Cowes: Least PETREL 
Coves—Halocyptena microsoma, I, 79, 90, V, 191. 
SaLvin—Halocyptena microsoma, 346. 
GopmMan—Halocyptena microsoma, xxxv, 6, pl. 3. 
According to Mr. Gifford’s notes, Least Petrels were: first 
noted by the Expedition on July 10, 1905, in latitude 30° 35’ 
N. and longitude 117° W., and were last seen on July 21, 1905, 
in latitude 23° 32’ N. and longitude 113° 4 W., none being 
observed in the vicinity of the Galapagos Islands or during the 
homeward passage. On San Benito Islands, Lower California, 
july 14, 15, 17, pairs were found at home among the rocks 
and, more rarely, under dead century plants. It was early for 
eggs; Mr. Beck, alone, was successful in the search, on the 
15th obtaining in a rock pile a single fresh one, together with 
the female parent. 
Like other short-legged storm petrels of the Northern Hemi- 
sphere, the Least Petrel is migratory, its fly-line apparently 
paralleling the coast from Lower California to Ecuador. 
Feather renewal is dormant and feather disintegration ac- 
tive in the seventeen Expedition specimens. The greater wing- 
coverts are much darker in some of these specimens than in 
others, natal brown supplanting the pale grayish brown. 
1 Mus. Vertebr. Zool., Univ. Calif. 
2 Carnegie Museum; New Zealand. 
