PLAUTUS. 19 



GENUS PLAUTUS BRUNNICH. (Page 10, pi. V., fig. 1.) 



Species. 



Upper parts uniform black, the secondaries sharply tipped with white ; lower 

 parts pure white. Summer plumage : Chin, throat, fore-neck, and sides of head and 

 neck, velvety dark snuff-brown, or soft blackish brown ; a large oval patch of white 

 covering the greater part of the space between bill and eyes ; bill black, its grooves 

 whitish. Length about 28.00-30.00, wing 5.75, culmen 3.15-3.50, greatest depth of 

 bill about 1.50. Egg (average size) 4.67 X 2.91, pyriform-ovate, pale olive-buffy, 

 variously marked with brown and black. Hob. Believed to be now extinct ; for- 

 merly (previous to 1844), coasts and islands of the North Atlantic, chiefly on the 

 American side ; south to Massachusetts Bay, north to the Arctic circle. 



33. P. impennis (LINN.). Great Auk. 



GENUS ALLE LINK. (Page 10, pi. VI., fig. 4.) 



Species. 



Head, neck, and upper parts black, the secondaries sharply tipped with white, 

 and scapulars streaked with the same ; lower parts white, the flanks striped with 

 dusky. Summer plumage : Sides of head and neck, with chin, throat, and chest, 

 uniform dark sooty brown. Winter adult : Chin, throat, etc., white, this color ex- 

 tending upward toward occiput ; feathers of chest dusky at base only. Young : 

 Similar to winter adult, but bill smaller and weaker, and colors duller. Downy 

 young : Uniform sooty slate-color, paler or more grayish below. Length 7.25-9.15, 

 wing 4.50-4.75, culmen .50. Egg 1.90 X 1-29, ovate, very pale bluish green or green- 

 ish white. Hob. Arctic Ocean and coasts of the North Atlantic ; on the American 

 side south, in winter, to New Jersey ; accidental on Detroit Eiver. 



34. A. alle (LINN.). Dovekie. 



