PROCELLARIID^. ii 



b. Partitioti between the nostrils very thin^ 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 of the lower mandible measured along the side; tarsus not 

 compressed. 



C. Wing more than twice the length of the tail; tail moderate, rounded 

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

 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. Wing less than twice the length of the tail; tail of 12 feathers long 

 and cuneate, 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 diredled 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 scarcely, 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 above the line of the ciilmen 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 culmen 

 when viewed from the side; compressed anteriorly and narrower than at the base; 

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



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



aa. Wing less than y.oo; tarsus not perceptibly longer than middle toe and 

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



Genus ^STRlBIyATA 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) ; auxilliaries 

 and under wing coverts mostly white inwardly, iuargined ivith dark. 



a. Larger and darker above; under tail coverts greyish dusky, very abruptly 



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



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



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



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



and longer tail coyerts spmetimes barred with dusky; wing 1 1.80-12.00, tail 5.50-5.75 



L267] ~ .... 



