NATURAL SCIENCES OF PHILADELPHIA. 65 



Description (from No. , Mus. Smiths., 9; San Diego, Jan. 21, 1862 ; a 



typical example). — Bill along culmen half as long as the skull, three-fourths 

 as long as the tarsus, as long as the middle toe and half its claw, very slender, 

 much compressed, higher than wide at the base ; culmen gently curved its 

 whole length ; rictus nearly straight; gonys perfectly straight; outline of the 

 very slender mandibular rami a little concave. Tarsus just as long as the 

 middle toe without its claw I Tip of inner lateral claw not reaching base of 

 middle one. Wings and tail of usual shape ; the latter contained about two 

 and a third times in the length of the former from the carpus. Under tail 

 coverts reaching (in this specimen) just beyond the end of the tail. Entire 

 upper parts uniform cinereous, not varied bj^ white. This color is slightly 

 darker, and more blackish-plumbeous on the head. It extends on the sides of 

 the head just to the eyes, the lids of which are of this color, a little further 

 down on the auriculars ; thence in a straight line along the middle of the 

 side of the neck to the shoulders ; thence in a straight line along the sides 

 under the wings, where it is nearly an inch broad ; the elongated feathers of 

 the flanks are also mostly of this color. Other under parts entirely pure white. 

 Under surface of wings entirely pure white ! Primaries black on the outer 

 web ; the greater part of the shaft and inner webs white; the terminal portion 

 of the shaft and inner webs brown. Tail feathers black, the inner webs some- 

 what brownish. Bill black, the base of the lower mandible whitish ; feet an- 

 teriorly dull yellowish, posteriorly dusky, in the present dried state ; " bill 

 black, feet whitish-blue, black below " (label). 



"Length 10-50; extent 17-50" (label); wing 4-80; tail 1-70; tarsus -95; 

 middle toe without claw -95, its claw -20; outer toe and claw 1-10 ; inner do. 

 •90; bill along culmen -80, along rictus 1-30, along gonys -45; depth at base 

 ■22; width -19.* 



The specimen above described, collected at San Diego, Cal., by Dr. J. G. 

 Cooper, is a little larger than the type, as will be seen by comparing the 

 measurements with those in the accompanying foot-note. It is also described 

 as representing the perfect plumage, — the type being imperfect in this respect. 

 The upper parts are of a uniform veiy dark cinereous, without a shade of 

 brown ; the latter hue only occurring in specimens with worn and faded 

 plumage. In the original description, here appended, the indications of tlie 

 size of relative lengths of. the tarsus and middle toe are made without 

 reference to the claw ; which fact explains an apparent discrepancy between 

 the present description and the original one. The tarsus is exactly as long as 

 the middle toe without its claw. 



This is a very strongly marked species. The most striking diagnostic feature 

 is the pure white of the under surface of the wings. In the uniformity of the 

 cinereous color of the upper parts it is also unique. Nearly the same length 

 of tarsus is found in B. brachyptcrun, Brandt, and Craven, Salvadori ; the 

 tarsus is much shorter than the middle toe in Wranffeli Brandt, marmuratus 

 Gm., ^' Kittlitzii" Brandt, and " brcvtrostris'^ Vigors. 



This species is certainly not the Uria hrevirostris Vigors, from San Bias. 

 This is described as having " alns suprii et infrci, tectricesque inferiores fuscffi, 



* * tarsi I," which settles all questions on this score. It has the same 

 dimensions, and the same relative length of tarsus and toes as Craveri Salva- 



* The following is tlie original description of the type specimen : " Bill slender and 

 slightly curved, about half the length of head. Tarsus scarcely shorter than the middle 

 toe [and claw]. Above dark brownish-blacii, the edges of the feathers with a decideil 

 plumbeous tinge; the side of neck below, and the axillars with the concealed portion of 

 the sides of the breast, ashy plumbeous. Entire under parts, including tail coverts and 

 inside of the wings, pure white, this color extending on the sides of the head so as to in- 

 clude the eyes; the lids, however, are tinged with dusky; bill black; legs apparently red- 

 dish in life. 



" Length 10 inches, extent 15-80, wing 4-70, tail 1-80, bill above -70, gape 1-20, tarsus -85, 

 middle toe [with claw] 1-00. This specimen is considerably weather-beaten, and the old 

 feathers of the upper parts are much worn, and bleached at the edges. The new ones are, 

 liowever, as described." 



1868.] 5 



