12 



BIRDS OF THE HAWAIIAN GROUP. 



(graduated for about 2.40), culmen 1.22, tarsus 1.40, middle toe witli claw 1.78. Hab. 



Middle Pacific from Hawaiian Islands to Galapagos (Ridgway). (No specimen in 



Museum.) 



13. M. phaeopyg'ia Sai.v. Dark-rumped Petrel. 



aa. Smaller and paler above; upper tail coverts ashy-grey, much less abruptly 



white beneath the surface (bill stouter) ; larger; under wing coverts mostly dark; feathers 



of the back distindlly edged with grey ; under parts white, except along the sides of 



fore breast. Female similar. Young: Smaller, with the under tail coverts as long as or 



longer than the tail feathers ; upper back and tail coverts much more broadly edged 



with blue-grey ; whole aspect of the back lighter ; less blue-grey on the sides of fore breast. 



Length II. 15-14.00 (12.75), wing7.40-8. 60, tail3. 20-4. 70, culmen i. 02-1. 10, tarsus i.io- 



1.15, middle toe i. 40-1. 50, inner toe 1.15-1.20. Hab. North Pacific Ocean. Laysan, etc. 



The following table will show the variation in measurements of young fledged birds 



and adults : — 



Juvenile (June ig ). 



Male. Female. 



II. 15 



Adult (September ) . 



lyeiigth II .50 



Wing 7.50 



Tail 3.70 



Culmen i .08 



Tarsus 1.15 



Middle toe i .50 



Inner toe i . 20 



7.40 

 3.20 

 1.02 



1-15 

 1.40 



I-I5 



PI. XIX., 7907, 7908. 



14- ^ 



Male. 



12.50 



8.60 



4-45 

 I. ID 



1.40 

 I-I5 



Female. 



i4.oo(?) 



8-75 

 4.70 



I. ID 



1.50 



I-I5 



hypoleu'ca Salv. Benin Petrel 



Genus BUI^WE'RIA Bonaparte. 



Plumage entirely dusky sooty brown, darker on the upper parts (smaller); 

 under tail coverts falling short of the end of the tail by more than .50 ; the greater 

 iving coverts lighter brown on their edges, forming a quite well defined patch ; quills 

 nearly black. Downy young: uniform dark sooty brown. lycngth about 10.00, wing 

 7.75, tail 4.50, culmen .90, tarsus 1.20. Hab. North Pacific Ocean. Laysan, Kauai, 

 French Frigates, Hawaii (Mills). 

 PI. XIX., 8768. 15. B. bul'weri (JARD. & Selby). Bulwer's Petrel. 



Genus PRIO'FINUS Hombr. & Jacq. 



Tail long, cuneate; under surface of body white; feathers of the head and upper 

 plumage not edged with white ; back, greater wing coverts and primaries entirely deep 

 sooty brown with slaty brown beneath ; feathers of the back edged with paler brown; 

 sides of the neck greyish, mottled; under tail coverts dusky; auxiliaries dusky. 

 Length c? 17.50 $19.00, wing 11. 25-12.00, tail 6.00, culmen i. 50-1. 55, tarsus 1.75, 

 middle toe 2.15-2.25. Hab. North Pacific Ocean. Laysan, Kauai, etc. 

 PI. XIX., 7928. 16. P. cunea'tus (Salvin). Wedge-tailed Shearwater, Unu kane. 



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