702 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



toes fully webbed and armed with strongly curved and sharp, though 

 not large, claws, the hallux always absent, the nostrils not overhung by 

 membrane, and the lores always densely feathered. The bill is 

 exceedingly variable in form, often quite unique in structure, but is 

 never acuminate. The wing is moderately large or rather small, with 

 relatively short secondaries, the longest primaries (usually the outer- 

 most only but sometimes the two outermost, the second always being 

 nearly as long as the first) exceeding the distal secondaries by appoxi- 

 mately half (sometimes a httle less, sometimes more than hah) the 

 length of the closed wing. The primaries are always more or less 

 bowed, and their coverts very large, covering nearly their basal half. 

 The tail is always short, the rectrices normal and 12 to 18 in number. 

 The tarsus is usually much shorter than the middle toe without claw 

 (longer only in Syntliliboramphus and Ejulomychura) , much com- 

 pressed, wholly reticulate or (in a few genera) with more or less dis- 

 tinct transverse scutella on lower or inner portion of acrotarsium, 

 rarely with a continuous series. The outer toe (without claw) is 

 always very nearly if not quite as long as the middle toe (without 

 claw), the inner toe as long as the fhst two phalanges of the middle 

 toe. In one genus {Synthliboramphus) the outer toe is longest and 

 the inner toe longer than Ih'st two phalanges of middle toe. 



Peculiar to the seas and coasts of the more northern parts of the 

 northern hemisphere, they represent there the Penguins of the 

 Antarctic seas. With one exception, however, they possess the power 

 of fhght, usually to a marked degree; but the Great Auk {Pinguinus 

 impennis), extinct since 1844, was quite unable to fly. The flight, 

 however, while rapid and strong, is direct and not buoyant as it is in 

 the Lari. 



Tlie family is represented by about 15 genera and 28 species, all of 

 the former and all but four of the latter occurring in North America. 



They nest in cavities among the rocks, usually on the face of clifts, 

 though some genera lay their eggs in burrows beneath the surface of 

 the ground, like most of the ProceUariidfe (Petrels). The single egg 

 is variable in form (which may be either pjTiform, ovate, or elongate- 

 ovate), even more so in color. The molt is said to be semi-annual. 



KEY TO THE GENERA OF ALCID^. 



a. Bill gallinaceous in form (short and thick, with distinctly curved culnien), its 

 width at posterior end of nostrils equal to its depth at same point, the gonys 

 exceedingly short (less than one-third the distance from gonydeal angle to 

 rictus); only 1 carotid artery. (Plautex) Plautus (p. 706). 



aa. Bill not gallinaceous in form; if short and thick, its width at jjosterior end of 

 nostrils decidedly less than its depth at same point; gonys relatively longer, 

 always longer than one-third the distance from gonydeal angle to rictus; 2 

 carotid arteries. 



