50 PROCEEDINGS OF THE ACADEMY OF 



or most of them, white or whitish in some portion or the whole of their 

 extent ; producing two patches of this color, not inaptly comparable to the 

 similar patches on the scapulars of Brachyrhamplnis Wrangeli, or Colli/rio 

 borealis, ia size, shape and general appearance. About half the secondaries, the 

 innermost ones, are quite conspicuously white on the tips of the outer web 

 for a fourth or a third of an inch. The forehead and lores, from the base of 

 the bill to the eyes and verte.x, are lineated (exactly as in microccros) with 

 sparse, distinct, Tery slender white setaceous feathers ; none are apparent, 

 among several specimens, behind the eye, or from the commissural angle of 

 the bill. Pallas tersely summed up these points of coloration of the upper 

 parts in saying " Fronte brachiisque albo-notatis ;" and the white about the 

 "arms" is a strong distinctive feature of the species in comparison with 

 microceros. The white of the under parts reaches far around on the side of 

 the neck ; on the side of the head it only extends on a level with the com- 

 missure ; it does not quite attain the base of the lower mandible, being cut 

 off from the bill by a small blackish-lead-colored area. There are indica- 

 tion of a small whitish spot just above and below the eye, formed of feathers 

 of the ordinary texture. The under wing coverts are wholly white, except 

 just along the edge of the forearm. The short tibial feathers are dusky 

 gray. Bill black, (as nearly as can be determined from the dried specimens,) 

 the base, gonys and tip of lower mandible yellowish. Posterior aspect of 

 tarsus, and inferior surface of toes and webs, blackish ; rest of legs and feet 

 a dull undefinable greenish-dusky (in the dried specimens.) 



The changes of plumage of this species are not known ; no other condition 

 than the one above described is represented by the specimens in the Smith- 

 sonian Institution, and none are contained, as far as known, in any other 

 American museum. No. 21,320 of the Smithsonian collection, obtained from 

 Capt. John Rodgers' expedition to the North Pacific, collected at Semiavine 

 Straits by Dr. Wm. Stirapson, is the one above described. No. 21,321, from 

 the same locality, is a younger bird, but entirely similar to 21,320, except that 

 it has a rather weaker bill, and only slight traces of the white setaceous feath- 

 ers on the forehead. No. 46,562, collected Sept. 9th, 1866, at Plover Bay, by 

 W. H. Dall, of the Western Union Company's Overland International Tele- 

 graph Expedition, a young bird, as shown by the soft feel of the feathers and 

 other features needless to detail, is referrible, with some degree of doubt, to 

 this species. The scapulars are very conspicuously white ; the secondaries 

 plainly tipped with white ; the under parts pure white, unspotted as in 

 typical pusillvs. The black of the upper parts is tinted, especially about the 

 head, with gray or plumbeous, and there are no traces of whitish setaceous 

 feathers on the forehead ; both of which features are to be attributed to the 

 juvenility of the specimen. The doubt in the case centres in the bill. This 

 oro-an has no trace of a tubercle, and is very small and weak, as usual in the 

 young pusillus : hut it see7ps to be deeper, and especially wider at the base, 

 compared with its length, than is the case with typical pusill us ; in these 

 points of shape approximating to microceros. But "seems to be" is the most 

 definite expression to be used in this case, for in the preparation of the spe- 

 cimen, or its subsequent drying or packing for transportation, the bill has 

 been injured, and so much distorted, that its true form cannot now be de- 

 termined with desirable precision. 



It cannot be denied that the relations that this species bears to microceros 

 are extremely intimate. So closely, in fact, does it approach the latter, that 

 its specific validity might fairly be called in question by one of conservative 

 views ; especially in consideration of the well-known fact, not to be disputed, 

 that the bills of all young Alcidx are much smaller and weaker, and even in 

 more striking points of form, conspicuously different from those of adult 

 birds ; and that a long time is required for their perfect development This 

 remark applies with especial force to the formation of the various knobs, 

 ridges, sulci, rictal callosities, and the other irregularities of surface. The 



[Jan. 



