346 



THE TUBE-NOSED SWIMMERS — TUBINARES. 



A. Culmen very concave ; leathers at base of maxilla extending in an angle nearly or quite to 

 the base of the nasal tube, that on the mandible forming a still more decided angle. 



1. D. exulans. Wing, 26.50-29.00 inches, ylr^u^^ .- White, the remiges blackish. Young: 

 Dusky, with fore part of head whitish (older individuals with more white). 



D. albatrus, adult. 



B« Culmen slightly concave, the bill more compressed ; feathering at base of maxilla extending 

 obliquely in a nearly straight line far back of the nasal tube, that of the mandible also 

 nearly straight. 



a. Latericorn narrower at base than in middle portion. (Phcehastria.) 



2. D. albatrus. Wing, 22.00-23.00 inches ; culmen, 5.50-5.60; depth of bill at base, 1.95- 



2.05; tarsus, 3.80-4.00; middle toe, 4.65-4.90. Adult: White, the pileum and nape 

 bright straw-yellov/ ; tail, remiges, etc., slaty brown, the shafts of the quiUs bright straw- 

 yellow ; bill grayish white, more yellowish on the unguis, and purple brownish on the 

 mandible; legs and feet grayish dusky. Young: Uniform sooty, the pileum and nape 

 blackish ; shafts of primaries bright straw-yellow ; bill pale horn-yellow ; legs and feet 

 grayish brown. Hab. Off the Pacific coast of North America (especially of Alaska). 



3. D. nigripes. Wing, 18.50-20.50 inches ; culmen, 4.00-4.25 ; depth of bill at base, 1.45- 



1.60 ; tarsus, 3.50-3.70 ; middle toe, 4.05-4.40. Uniform dusky (more grayish below), 

 the crissum, upper tail-coverts, and base of the tail white in the adult ; anterior portion 

 of the head whitish ; bill dusky purplish brown ; legs and feet black. Hab. Pacific coast 

 of North America. 



b. Latericorn much broader at base than in middle portion. (Thalassarche.) 



4. D. melanophrys. Wing, 19.50-20.00 inches ; tail, 8.00-8.50 ; culmen, 4.30-4.70 ; tarsus, 



3.00-3.25 ; middle toe, 4.00-4.30. Adult : Head, neck, rump, upper tail-coverts, and 

 entire lower parts white, the side of the head with a more or less distinct grayish stripe, 

 darkest immediately before and behind the eye ; back and scapulars brownish slate, more 

 ashy anteriorly ; wings uniform dark brownish slate ; tail brownish gray, the shafts of 

 the feathers yellowish white. Bill yellowish, the ungui and base of culmen sometimes 

 (in younger individuals?) tinged or clouded with grayish ; legs and feet "pearly slate." 

 Hab. Southern oceans; casual (?) off coast of California. 



