454 



LAMBLLIEOSTRAL SWIMMERS — ANSERES. 



The eggs of tliis species, in shape and general appearance, are i;ndistinguishable 

 from those of the Snow Goose. Thej are of a uniform dull-white color, and measure 

 about 2.80 by 2.00 inches. 



Genus BERNICLA, Stephens. 



Bemicla, Stephen.s, Gen. Zool. XII. ii. 1824, 45 (type, Anas bernicla, Likn. ). 

 Zettcoparcia, Reich. Sj'st. Av. 1853, pi. ix. (type, A-nser Uiicopsis, Bechst. ). 

 Leucobleplmron, Baird, B. N. Am. 1858, 763 (type, Anas canadensis, Linn.). 



With much the same form throughout as the species of Anser, those belonging to the genus 

 Bernicla are distinguished hy the darker plumage, with the head and neck chiefly black, and 

 the bill and feet enthely deep black, at all ages. All the known species of Bernicla (as properly 

 restricted) occm- in North America, and may be defined as follows : — 



B. canadensis. 



Head aud neck black, with a somewhat triangular patch of white on each cheek, usually con- 

 fluent underneath the head, but sometimes separated by a black stripe or "isthmus" 

 alons the throat ; in some specimens a white collar around the lower neck. 



1. B. canadensis. Tail-feathers 14 to 20 inches ; wing, 13.60-21.00 ; culmen, .95-2.70 ; tar- 

 sus, 2.10-3.70 ; middle toe, 1.80-3.40. Tail, rump, and primaries browniish black ; upper 

 tail-coverts, erissum, and anal region white ; rest of the plumage grayish brown, lighter 

 below, the feathers tipped with paler Hah. Whole of North America, south to Mexico. 



Head, neck, and jusulum black,_the middle of the neck with a white patch on each side, or a 

 wide collar of the same, interrupted behind. 



