^?89r''] PROCEEDINGS OF THE NATIONAL MUSEUM. 599 



Type, No. 128,835, U. S. Nat. Miis., Aldabra Islaud, October 10, 

 1892; Dr. W. L. Abbott. Length (before skinning-), 12.50 inches, 

 "irides chestnut-brown; feet blackish brown; bill black, base pink." 



Eight adnlts from Aldabra compared with four from Assumption 

 Island agree in the above-mentioned characters. In the type, there is 

 scarcely a trace of white bars on the abdomen, while those on the 

 flanks and thighs are nearly obsolete. Other specimens, however, 

 have these markings well developed, though never so broad and distinct 

 as in R. gidm'is, w^hile in none of them is there even a trace of the 

 blackish streaks on the back, which are very conspicuous in all the 

 birds from Assumption. 



^ 5. Ibis abbotti sp. nov. 



Sp. Ciiab. — Similar to I. heruieri, as distinguished from I. a'thiopica 

 but lower neck naked and minutely papillose; remiges without dark- 

 colored tips (blackish gray in J. bernieri, dark metallic green in J. a'thi- 

 opica) ; decomposed tertials greenish blue on outer, grayish green on in- 

 ner, webs and iris light blue instead of w^hite. 



Hab. — Aldabra Island. 



Type, No. 128,812, female ad., Aldabra Island, October 8, 1892; Dr. 

 W. L. Abbott. 



6. Sula abbotti sp. nov. 



Sp. Char. — Most like S. cyanops^ but bill much more robust, and color- 

 ation different, the prevailing color of the wings and tail deep black in- 

 stead of grayish brown, the wing-feathers (both remiges and coverts) 

 with inner webs and bases largely and abruptly pure white, and the 

 upper tail-coverts and flanks marked withguttate or w^edge-shaped spots 

 of black. 



Adult male (type. No. 128,761, Assumption Island, Indian Ocean, Sep. 

 tember 18, 1892 ; Dr. W. L. Abbott) : Head, neck, back, rump, upper tail- 

 coverts, and entire under parts pure white; scapulars and wing-coverts 

 pure white basally, grayish black terminally, the former mostly con- 

 cealed, but frequently exposed as angular spots, or streaks, particularly 

 on the lesser and middle wing-coverts ; greater coverts with inner webs 

 pure white, except at tip ; remiges and primary-coverts black superfi- 

 cially, but inner websof secondaries chiefly (those of innermost feathers 

 wholly) pure white, and those of the primaries also largely pure white, 

 this color reaching to the shaft on the basal portion of the first quill, 

 which also has the outer web white, and the shaft yellowish white, at 

 base; on the innermost primary the white forms a broad edging which 

 extends nearly to the tip, gradually running out to the edge, but at the 

 base occupying the entire width of the w^eb. Tail deep black, the feath- 

 ers (except middle pair) sharply tipped with pure white, and broadly 

 edged with the same at the base. Each of the upper tail-coverts has a 

 large wedge-shaped median spot of black, and many of the feathers of 



