THE RAZORBILL. 791 



length of head, more or less laterally compressed. Feet webbed, 

 hind toe absent or rudimentary. In some species part of the horny 

 coverings of bill are cast off after breeding season, thus greatly alter- 

 ing appearance of bill. Femur very short. Basipterygoid processes 

 absent or indicated. Sternum with two pairs of incisions. Dorsal 

 and ventral ribs rather long. One family with about 12 genera, all 

 in northern regions of northern hemisphere. Eggs as a rule enor- 

 mous in comparison with size of birds, in which they are only 

 surpassed by Kiwis (Apteryx). 



Family ALCID.E. 

 Characters of Order Alcce. 



Key to genera of Order Alc^e. 



-. /Wing under 135, bill under 25 mm Alle 



\ Wing over 135, bill over 25 mm 2 



9 /Bill orange-red Fratercula 



z \ Bill black or bluish 3 



o /Bill short, with cross -grooves and folds Alca 



\ Bill elongated, without cross-grooves or folds . . . Uria 



Genus ALCA L. 



Alca Linnaeus, Syst. Nat., Ed. x, i, p. 130 (1758 — Type by subsequent 

 designation and Linnean tautonymy : " Alca ,, =Alca torda). 



Bill strongly laterally compressed, in adults with vertical 

 grooves and folds, strongly decurved at tip, basal part feathered 

 for nearly half its length. Nostrils slit-like, almost hidden in front 

 of feathering. Tarsus shorter than middle toe with claw. Tail 

 with 12 to 14 rec trices. 2 species. The Great Auk is often generic - 

 ally separated, because its wings being even smaller than those of 

 Alca torda, were inadequate to support the large body and the 

 bird was therefore unable to fly, but as the wings are developed 

 and only much smaller in proportion, this is not a good generic 

 character. Number of rectrices the same or 2 more — statements 

 of 16 or 18 apparently wrong ; individual variation of 12 and 14 

 occurs also in other Alcce. If separated generically the name must 

 be Pinguinus 



ALCA TORDA 



465. Alca torda L.— -THE RAZORBILL. 



Alca Torda Linnaeus, Syst. Nat., ed. x, i, p. 130 (1758 — "Habitat in 

 Europse borealis oceano." Restricted typical locality : Southern Sweden). 

 Alca torda Linnaeus, Yarrell, iv, p. 55 ; Saunders, p. 695. 



Description. — Adult male and female. Winter. — -Head, back of 

 neck and whole upper-parts black, slightly tinged brownish (back 

 of neck occasionally mottled with white) ; lores as upper-parts ; 

 from base of culmen to centre of anterior edge of eye a thin and 



