REMARKS ON THE GENUS SULA. 309 



el Bill horny greenish grey, the point more yellowish horny, 

 the base of the bill and the naked skin of the head blackish. 



a Younger bird (M c Kean's Isld.) — Almost like the above, but 

 on the back a few brown feathers ; the rump is still almost 

 uniform brown ; the upper tail coverts are white, with brown 

 tips. 



" Younger bird (? Texas) . — The entire upper surface nearly 

 uniform brown, only on the scapulars, mantle, and rump appear 

 many white feathers, most of which however still show a 

 washed-out brown spot in the middle. Many of the upper 

 wing coverts exhibit white tips ; so also the brown feathers 

 of the foreneck. The rest of the lower parts, together with 

 the lower wing coverts, pure white. 



" Bill horny brown, the edges and tip pale horny green- 

 ish ; naked portion of face and throat brownish black ; feet 

 dirty horny brown. 



a This specimen agrees almost entirely with the young speci- 

 men of S. melatwps, figured, Ibis, 1859, pi. X, f. 2. 



" Young. — Almost uniform grey brown (Suudev). 



" Nestlings clad in white down. 



" Sexes do not differ, only the young and females are smaller. 



" Young. — Female ; face and bill for the basal half blue ; the 

 terminal portion olive-coloured ; feet olive-coloured ; the webs 

 dark ; iris deep yellow. 



" Young. — Bill almost to the base, olive-coloured (Sundeval, 

 from fresh specimens). 



" Old. — Bill and naked portion of head bluish green ; legs 

 dirty green ; iris greenish yellow (Graffe, from fresh 

 specimens.)" 



They add dimensions of numerous specimens, some of which 

 I have already given : — 



" L. W. T. B. at fr. B. fr. gape Trs. M. T. 



31-8— 32-86 18 6"02 4-3 53 2-53 312 Young (?) Texas. 



167 5-5 3-83 4'58 2-03 2'94 Young 



17 75 6-45 4-02 ... 2-1 294 (cyanops, Sundev.) 



19-18 10-13 4-48 5 68 2-42 33 {cyanops. Pelz.) 



15-7—17-43 7-12—8-03 442 ... 1-85—1-94 ... Schlegel. 



17.52—18-33 8-77 442 4-93 2-2 ... (melanops. Hartl.) 

 To which we may add :— 



30-7—31-8 17-8—18-1 7-67—8-77 4-12 493 2-1-2-2 ... v. Heuglin. 



29 16-5 8-5 ... 5* 2-25 ... Gould. 



32 16-5 7-25—7-5 40—4-06 4'12-5 2-15— 225 295 Butler." 



If therefore we believe that these measurements all refer to 

 the same species, we must admit that the wing varies from 15*7 

 to 19-18 ; the tail from 5-5 to 10-13 ; the bill at front from 3"83 

 to 4*48 ; and from gape from 4*58 to 5-3. Similarly, the tarsus 

 varies from 1-85 to 2*53, and the mid toe in the few measure - 



* It is impossible to say whether this dimension sliould be placed in this or the 

 next preceding column. Mr. Gould merely says " Bill, 5." 



p 15 



