NATURAL SCIENCES OP PHILADELPHIA. 15 



III. — Descriptions of Genera and Species. 



1. Subfamily Alcin^e. 



ALCA, Linnseus, 



Chenalopex, Moehring, Ar. Gen. 1752, p. 65, No. 68. 

 .4/ra, Linnasus, Syst. Nat. i. 17."i8 ; and of authors. 

 ringuinus, Bonnatei-re, Ency. Method. Orn. 1790, p. 28. 



Size largest in the family. Form heavy, compact, robust. Head large, 

 ovate, produced forwards. Neclv moderately long, thick. Wings morpho- 

 logically perfect, teleologically rudimental, not admitting of flight, in length 

 from carpal joint to end of longest primary scarcely twice as long as tail ; when 

 folded not reaching the tail. Tail short, pointed. Legs short and stout. 

 Webs broad and full. Tarsi compressed ; their anterior ridge and superior 

 surfaces of toes scutellate, lateral and posterior aspects reticulate, the plates 

 on the latter very small. Tibiaj feathered nearly to the joint. Bill about as 

 long as the head, large, strong, very deep, exceedingly compressed. Upper 

 mandible with culmen about straight for half its length, then regularly con- 

 vex, tip obtuse, declinate, scarcely overhanging; a deep groove on its side at 

 base, parallel with the outline of feathers ; its side then perfectly smooth for a 

 space, then deeply impressed with six to ten oblique curved sulci. Gape very 

 large, running far back ; line of commissure nearly following that of culmen. 

 Eniinentia symphysis slight ; gonys nearly straight. Lower mandible two- 

 thirds as deep as upper, its sides impressed with six to ten straight, vertical 

 sulci. Feathers about base of mandibles short, very compact : extending 

 downwards from base of culmen, a little forwards, to commissural edge of 

 upper mandible ; reaching much further on sides of lower mandible ; wholly 

 covering the moderately long, very narrowly linear, impervious nostrils, which 

 are situated just above the commissure. 



It is unnecessary to compare this genus with any other. Utainania, most 

 closely allied, is at once distinguished by its teleologically perfect wings, 

 though nearly identical with Alca in other points of structure. The only 

 known representative of the genus is remarkable, both for its large size, and 

 for not possessing the power of flight, in consequence of which it may be said 

 to represent, in the Northern Hemisphere, the numerous Penguins of the 

 Southern. By many ornithologists it is believed to have very recently become 

 nearly or quite extinct. 



Rigid adherence to the law of priority would necessitate the use of a differ- 

 ent name for this genus. "Alca" was first applied by Linnajus, in 1744, to the 

 genus of which the bird now called Fratercula or Mormon arcticus is typical ; 

 and even as used by LinniBus in 1758 it has torda as its recognized type, ac- 

 cording to that rule which regards the species first mentioned as type, when 

 none is otherwise indicated ; so that it cannot, with strict propriety, be used 

 at all in this connection. But the name has become so firmly established by 

 common consent and long usage, that it would be ruthless, as well as profit- 

 less, to attempt its supercedure by Chenalopex of Moehring, 1752 ; particularly 

 as this latter word has come into extensive employ for an Anserine genus. 

 The genus Alca, as framed by Linnwns in 1758, included both torda and im- 

 pennis : and when restricted, by the generic separation of these two types, there 

 seems no good reason why the first mentioned should be regarded as more 

 peculiarly typical of the genus than the last. Should Alca be reserved for 

 Fratercula arctica, or for Utamania torda, it will be apparent that numerous un- 

 warrantable innovations necessarily follow; while its employ in connection 

 with impennis entails no such consequences. 



Alca impenxis Linn. 

 Chenalopex, Moehring, Av. Gen. 1752, p. 65, No. 68. "Rostrum conoides, 

 conuexum, ad latera compressum, aliquot sulcis transuersis canalicula- 



1868.] 



