KO.U16. PROCEEDIXCS OF THE XAIIOXAL MUSEIM. 655 



AfluH male.— No. 132763, U. S. N. M.; Wenman Islaud, Galapagos, 

 April 4, 1891 ; C. H, Towiiseiid. Above uuiform very dark sooty, with a 

 faint gTeeiiish slaty gloss in some lights; greater wing-coverts broccoli 

 brown, producing an oblique band across the wing; remiges and pri- 

 mary coverts dull black; upper tail-coverts white, the longer ones 

 abruptly tipped with black ; tail black, with the concealed basal por- 

 tion of the four outermost rectrices white, this most extensive on tlie 

 lateral pair, where partly exposed beyond the coverts. Under ])arts 

 deep sooty grayish brown (much lighter than upper parts), the sides of 

 the crissura and the lateral under tail-coverts (also basal portion of 

 longer median ones) white. Bill, legs, and feet wholly Idack. Length 

 (skin), 7.20; wing, 5.85; tail, 2.80, forked for 0.15; culnien, O.Gl; nasal 

 tubes, 0.30; depth of bill in front of nostrils, 0.20; tarsus, 0.88; middle 

 toe, 0.85. 



This species, while bearing a superficial resemblance to 0. leucorhoa, 

 Vieillot, is in reality quite different in several very obvious particulars, 

 as follows: (1) The upper tail-coverts are pure (instead of grayish) 

 white, terminated by a narrow band (about 0.30-0.50 of an inch wide 

 at the broadest part) of black. (2) The rectrices (except two middle 

 pairs) are pure white basally, the next to the middle pair being pale 

 grayish on the basal iiortion. (This white is mostly concealed by the 

 tail-coverts, but is partly exposed on the lateral pair, partly on account 

 of the greater extent of the white itself, but also because the lateral 

 coverts are shorter than the middle ones.) (3) The greater wing-coverts 

 and outer webs of the tertials are much darker, offering less decided 

 contrast with the general color of the wings. (4) The tail is far less 

 deeply forked, the difference in length between the longest and shortest 

 rectrices being from 0.15 to 0.30 of an inch instead of 0.75-0.90. The 

 tarsus is also shorter, and there are additional minor differences scarcely 

 worth noting. 



0. cryptoleucura is, however, much more closely related to 0. macro- 

 dactyJa (Bryant)' of Guadalupe Island, Lower California, which also 

 has the black tips to the longer upper tail-coverts and the concealed 

 white at the base of the tail. 0. macrodactyla is much larger, however, 

 (wing r).H>-6.70, tail 3.30-3.90), the tail much more deeply forked (depth 

 of fork 0.90-1.40), and feet lu'oportionally larger (tarsuc 0.8G-1, middle 

 toe with claw 1.10-1.18). 



lioth species are typical members of the subgenus Cymoeliorea, Coues, 

 having very prominent nasal tubes, the outer toe longer than the mid- 

 dle, the latter (including its claw) about e(jual to tlie tarsus, and the 

 first primary shorter than the fourth, as in the type species {O. leu- 

 corhoa). 



' Oceauodroma leiicorhoa macrodactyla, Bryant, I'roc. Cal. Ac. Sci., II, 1887. — 

 (Guadalupe Island, Lower California ; collection of W. E. Bryant). 



Oceauodroma macrodactyla, American Ornithologists' Union, Check List, 

 abridged ed. 1889, No. 1061. 



