50 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4TH SER. 
Nostrils separated by a thick partition 
Nasal tubes not bevelled; nostrils only partially visible from above 
Back, breast, and abdomen dark 
Chine white ee ee Ss re penionat a Procellaria equinoctialts 
Chin) dark.) soos lan SR es NU, Neon PLR oe Grin na ace P. parkinsom 
Back gray; breast and abdomen white............ Priofinus cinereus 
Nasal tubes bevelled anteriorly; both nostrils visible from above 
Tail not decidedly wedge-shaped 
Lower parts white, or chiefly so 
Wing not under 11 in. (279 mm.) 
Pileum/ dark brown! ee aces ose cone sae cee Puffinus gravis 
Pileum gray 
Lower tail-coverts wholly, or almost entirely white..... 
Lower tail-coverts largely dark-colored................. 
BY Sam eaMrarat ea RENE pte tes let ielia ates P. creatopus (light phase) 
Wing under 11 in. (279 mm.) 
Lower tail-coverts largely dark-colored 
Upper parts and dark color of lower tail-coverts brown; 
wing not under (6:8. in. (223mm) sen eee ee oe 
ea stains ey cee ati P. puffinus (brown-backed phase) 
Upper parts and dark color of lower tail-coverts dark brown 
or black 
Upper parts dark brown; axillaries narrowly and evenly 
tipped with white; wing not under 8.8 in. (223 mm.) 
EBA co Ne Citak UR THO AMES: tate ora ai at P. opisthomelas 
Upper parts black; axillaries not narrowly and evenly 
tipped) with white ee aie aa a cena P. auricularis 
Upper parts dark brown; wing under 88 in. (223 mm.) ; 
tail decidedly more than twice the length of exposed 
culmeni i. Geen P. obscurus (brownish-backed phase) 
Lower tail-coverts wholly, or almost entirely white 
Upper parts sooty black or blackish brown 
Fore-neck not invaded by dark color of sides of neck; 
axillaries white, subterminally dark gray or sooty black; 
wing, not under S.8. in. |(223 mim) deere erie ere 
CEES Us BO. SIN ISN Ta P. puffinus (black-backed phase) 
Fore-neck more or less invaded by dark color of sides of 
neck; axillaries brown..P. gavia (brownish-backed phase) 
Upper parts bluish black or plumbeous 
Tail less, or but little more, than twice the length of 
exposed culmen......... P. gavia (bluish-backed phase) 
Tail decidedly more than twice the length of exposed cul- 
men; wing under 8.8 in. (223 mm.)................ 
ESET A Nem aR ALA MENTE tiie P. obscurus (bluish-backed phase) 
Lower parts white obscured by gray....P. creatopus (dark phase) 
Lower parts (white obscuredaby prowiscun means oe 
Ee Pere A enete ian i ates ulseat) P. puffinus (extreme brown phase) 
Lower parts dark 
Latericorn light-colored isan as eee scare ete P. carneipes 
Latericorn not light-colored 
Breast and abdomen dark gray 
Exposed culmen over 1.4 in. (36 mm.)............. P. griseus 
Exposed culmen not over 1.4 in. (36 mm.); bill at base rela- 
tively, sometimes actually, wider than in P. griseus 
sig ned Uae atl a RUA CMe UB DI MOAI CAT telnet P.  tenuirostris 
Breast, abdomen, and under wing-coverts dark brown... 
Pera ny Or AM oa airy aN Gh A eS Ghat A P. nativitatis 
