PROCELLARIID^. ii 



b. Partition betiveen the nostrils very thirty i. e., narrower than the width of 

 a single nostril and within the nasal tube; depth of the bill at the shallowest part more 

 than one-fourth the length oj the loiuer mandible measured along the side; tarsus not 

 compressed. 



C. ]Ving more than tiuice the length of the tail; tail moderate, rounded 



— (i2 feathers); nasal tubes diredled straight forward (claw of hallux small, .10); nail 



S of lower mandible making up more than one-third the length of the mandible measured 



along the side. Plumage and size differing among species. . (Page 11.) ^strela'ta. 



CC. Jf^ing less than tzi'ire the length of the tail; tail of 12 feathers long 



and ciineate, being graduated for a third of its length ; nail of the lower mandible making 



up less than a third of the length of the mandible measured along the .side ; plumage dark; 



nasal tubes fleshy at ends and direcfled forward and upward. . (Page 12.) Bulwer'ia. 



bb. Partition between the nostrils thick, i. e., thicker than the outer edge of 



one of the nostrils ; the partition scarcelj-, if any, shorter than the outer edges of the 



tubes; tarsus compressed and with a ridge on the front edge; space between the end 



of the nasal tubes and the base of the unguis ( nail on the tip of upper mandible ) more 



than the length of the latter (nostrils at least partially visible from above; wings 



less than 15.00). 



d. Nostrils elevated aboz'c the line of the cnhnen when viewed from 

 the side ; nasal tubes elevated and inflated anteriorly ; under wing coverts dusky; 



breast white (Page 12. ) Prio'finus. 



dd. Nostrils not noticeably elevated above the line of the cuhnen 

 when viewed from the side; compressed anteriorl}- and narrower than at the base; 

 edge of nostrils entirelv visible from above ( under wing coverts white or else lower 



parts dusky) (Page 13. ) Puff'inus. 



aa. JJ'ing less than ]'.(>(>; tarsus not perceptibly longer than middle toe and 

 claw; tail forked, or at least emarginate ( Page 13. ) Oceano'droma. 



Gexus ^STR:EI,ATA Bonaparte. 



Exposed portion of inner web of primaries beneath dark ; bill wide at the gape; 

 under parts mostly white ; crown and back of the head dark ; upper tail coverts uniform 

 with the back ; tail dusky (outer feathers sometimes mottled with white) ; anxilliaries 

 and under iving coverts mostly ivhite inivardly, margined u'ith dark. 



a. Larger and darker above; under tail coverts gre3-ish dusky, ver}- abruptly 



white beneath the surface; upper parts, including hind neck and upper tail coverts, 



uniform brownish slate, darker on the wings and tail, and nearlj- black on the head; 



the feathers of the hind neck and upper tail coverts (the latter yery abruptly) white 



beneath the surface; forehead, lores, cheeks and entire lower parts white; the sides 



and longer tail coverts sometimes barred with dusky; wing 11.80-12.00, tail 5.50-5.75 



L267] 



