BIRDS OF NORTH AND MIDDLE AMERICA. 701 
of femur; first digit of manus absent; tarso-metatarsus not laterally 
compressed; tensor patagii and biceps slip -peculiar (distinctive) ; 
expansor secundariorum absent; thigh-muscle formula without Y, 
sometimes (usually?) without B (ABX —AX —,or AX +), theambiens 
always absent; only 1 brevis tendon; ceca absent or small (mere nip- 
ples) ; intestinal convolutions of numerous (not less than six) loops; gall 
bladder present; crop absent; tongue generally fleshy, elongated, tri- 
angular, spiny only at base; anterior toes always fully webbed, the 
third (middle) one longest; hallux always absent; young ptilopedic, 
tardily nidifugous (nearly nidicolous). 
Oil gland tufted, its apertures 2-8; aftershaft present; secondaries 
aquincubital; dorsal pteryla without break between anterior and pos- 
terior parts; ventral pteryla dividing much posterior to neck; rec- 
trices, 12-18. - . 
The Alce differ from the remaining Charadriiformes in possession 
of all the above characters, and therefore seems to be more distinct 
as a group from the Lari and Limicole than these are from one 
another. 
By some systematists (notably Sclater, Stejneger, and Beddard) the 
Alcz are placed in the same suborder with the Loons (Gaviide) or 
one including both the Loons and the Grebes (Colymbide). Un- 
doubtedly the Auks and Loons are closely related; but the evidence 
seems to point to a closer relationship of the former to the Gulls than 
to the Loons. The latter differ in their holorhinal (instead of schizo- 
rhinal) nostrils which, externally, are operculate; well-developed 
(long) instead of absent or rudimentary (nipple-like) ceca; presence 
of a powerful cnemial crest to the tibia, and possession of an ambiens 
nouscle and a well-developed hallux. In the Alce the rectrices are 12 
to 18 in number, while in the Gavide they number 18-20. There are 
also other differences, which it is unnecessary to mention here. 
Family ALCIDA. 
THE AUKS. 
= Brachyptert ViEtLLoT, Analyse, 1816, 66. 
= Alcade Viaors, Trans. Linn. Soc. Lond., xiv, 1825, 498. 
= Alcide Barren, Rep. Pacific R. R. Surv., ix, 1858, 755, 819, 900.—LizLJEBorG, 
Proc. Zool. Soc. Lond., 1866, 15.—Covsrs, Key N. Am, Birds, 1872, 338; 2d 
ed., 1884, 797.—Carus, Handb. Zool., i, 1868, 366.—Bairp, Brewer, and 
Ripeway, Water Birds N. Am., ii, 1884, 420, 461.—Srzsnecer, Standard 
Nat. Hist., iv, 1885, 69.—AmEricaNn OrnniTHoLoaists’ Union, Check List,1886, 
76; 8rd ed., 1910, 25.—Ftrerincer, Unters. Morph. Syst. Vég., ii, 1888, 
1148.—Suarps, Review Rec. Att. Classif. Birds, 1891, 72; Hand-list, i, 1899, 
xiv, 180.—Gavow, Classif. Vertebr., 1898, 35.—Satvin and Gopman, Biol. 
Centr.-Am., Aves., iii, 1904, 446.—Know tron, Birds of the World, 1909, 49, 
396. 
The Alcide are aquatic (swimming and diving) sea-birds with the 
legs attached near the rear end of the body (pygopodous), the anterior 
