436 



LAMELLIROSTRAL SWIMMERS — AN8ERES. 



it by Mr. D. G. Elliot, since the <lifferciice in the churactor of the bill from that of the typical 

 species of the geuiw i» hurdly of generic value. The »i)ecie« may be distinguished an follows : — 



Synopsis of Species. 



A* Plumage never chieHy white ; the lulult mainly griiyinh brown, with bluish-gray rump and 

 wing-ooverts, tlie head and part of the neck white. Young almost wholly gruyish brown, 

 including head and neck. 



1. C. oaeruleaoeiM. Bill very robust, tlie posterior lateral outline of the muxilhi decidedly 



concave ; coniiuissure wiilely giiping, and lower outline of the mandible decidedly convex. 

 Wing, about 1.').(K»-17.<H) inches; culnien, 2.1(1-2.30 ; tui-sus, ;j.(H»-;j.3(i ; michlle toe, 2.1.') 

 -•2M). Hal). Interior of North America; Mississippi Valley, chielly in winter. 

 B« Plumage of the adult pure white, the primaries black, more grayish towaiil the base; young 

 grayish white, the cenires of the feathers darker gray. 



2. C. hyperboreus. 15111 robust, and shaped like that of C. (•(rrn/fgccjw. Wing, 15.(K)-1H.5() 



inches; culmen, I.!»r)-2.H(); depth of ma.xilla at base, l.l.')-1.5() ; tarsus, 2.80-3.50; 

 middle toe, 2.IO-2.IM). //<(/). The whole of North Ameiica. 



3. C. RosiL Hill small, the posterior lateral (mtline of the maxilla almost perfectly straight, 



the toiuia closely a|>proxi mated, and the lower outline of the numdible scarcely convex ; 

 in older specimens the biwe of the maxiUa corrugated or warty. Wing, I3."r)-I.'")..')0 

 inches ; culmen, l.."iO-1.70 ; depth of nmxilla at base, .85-.95; tarsus, 2.30-3.00 ; middle 

 toe, 1.80-2.05. Hub. Northwestern North America. 



Chen csBrulescens. 



THB BIVE-WINOEO OOOSE. 



Ams cfrmlfseens, Linn. S. N. ihI. 10, I. 1758, 124 ; n\. 12, I. 17tiO, 108. — Gmel. 8. N. I. 1788, 



513.— I-ATH. hul. Om. II. 1790, 830. 

 A)U)er cicnilfsceiit, Vikii.i,. Kiic. Meth. 1. 1823, 115. — Baiiid, Cat. N. Am. B. IS.'iU, no. 664. - 



CoUEs, Key, 1872, 282 ; Check List, 1873, no. 471» ; Birds N. W. 1874, 553. 

 C/icn camhscciis, liimiw. I'roc. \J. S. Nat. Mus. Vol. 3, 1880, 202 | Norn. N. Am. B. 1881, no. 



590. — CoL'Ks, Check List, 2a ed. 1882, no. 094. 

 Aiiscr hyihrhorcua (supiKistHl young), .Steimiens, Shaw's Gon. Zool. XII. ii. 1824, 33. — B/Viitit, 



B. N. Am. 1858, 760. 



Hab. North America in general, but chiefly the interior. 



Si*. Char. Adult: ifead and upper half of the neck white, or mostly white, the former fre- 

 ([uently washed with orange-rufous anteriorly ; lower neck and Ixxly grayish brown, the feathers 

 bonlereil terminally with paler, these pale edgings, however, ni^arly obsolete on the neck, where 

 the tint is darker, inclining to idunil)eous-umlier, which joins irregularly against the white above 

 it. Rump and wings plain ^learl-gray or bluish cinereous (the former sometimes white), in strik- 

 ing contrast to the deej) giiiyish brown of the scapulai's, sides, etc. ; that of the rump fading into 

 white on the upper tail-coverts, and that of the greater coverts edged ex rnally with the same. 

 Primaries black, fading basidly into hoary gray ; secondaritfs deep black, narrowly skirt(>d with 

 white ; tail dee|) cinereous, the feathers distinctly borilered with white. Hill reddish, the com- 

 missund space black ; feet re(hlish. YoiDig : Very similar, but the chin, only, white, the rest of 

 the head and neck being uniform pluniljeous-umber or brownish plumbeous, like the breast, only 

 darker in shade ; bo<ly more cinereous than in the adult, the pale tips to the nearly truncated 

 contour-feathers being obsolet<'. Rump, wings, and tail as in the adult. Bill and feet blackish. 

 Downy young, not seen. 



Total length, alx)ut .30.00 inches; wing. 15.00-17.00 ; culmen, 2.10-2.30 ; tarsus, 3.00-3.30 ; 

 middle toe, 2.1.'j-2.50. 



The chief variation in the ]ilumage of adults of this species consists in the extent and continuity 

 of the white of the neck. This is usually more or less broken, the dusky of the lower portion 

 ninning upwards in invgular spots or projections ; it extends highest on the nape, where it some- 



