GREAT AUK. 317 
declinate. Upper mandible with the dorsal line straight for an inch 
and a quarter, then declinate and decurvate to the end, the ridge very 
narrow, broader at the base; the sides nearly flat, with a basal ridge 
succeeded by a deep groove, then a large flat space, succeeded by eight 
oblique curved ridges, the edges sharp toward the end, the tip decur- 
ved and obtuse. Nostrils marginal, linear, short, pervious, but con- 
cealed by the feathers. Lower mandible with the angle long, the sides 
extremely narrow and linear for half their length, the horny part not 
being extended over the bone, which is covered with feathers, after- 
wards deep and compressed, with the dorsal line at first convex, then 
ascending and concave to the end, the sides flat, with about ten trans- 
verse ridges, the edges sharp. the tip deflected. 
Head large, oblong, anteriorly narrowed. Eyes rather small. Neck 
short and thick. Body compact and full. Wings extremely small, but 
perfectly formed. Feet placed far behind, short, very strong; tursus 
short, compressed, anteriorly scutellate, laterally covered with angular 
scales, those on the hind part very small. Hind toe wanting; third 
toe longest, outer nearly as long, inner much shorter, lateral toes mar- 
ginate, all with numerous scutella and several rows of angular scales 
above, and connected by reticulated webs. Claws rather small, nar- 
row, arched, convex above, and obtuse. 
Plumage close, blended, very soft, on the head and neck short and 
velvety. Wings diminutive, much pointed; the primaries tapering 
to an acute point, the first longest, the rest rapidly graduated, their 
coverts long; secondaries short and broad, scarcely longer than their 
coverts. Tail short, pointed, of fourteen feathers. 
Bill black, with the grooves between the transverse ridges white. 
Iris hazel. Feet and claws black. Fore part of the neck below, and 
all the lower’ parts white, of which colour also is a large oblong patch 
before each eye, and the tips of the secondary quills; the rest black, 
the throat and sides of the neck tinged with chocolate-brown, the wings 
with greyish-brown, the head, hind neck, and back glossed with olive- 
green. ; 
Length to end of tail 29 inches, to end of wings 233, to end of 
claws 314, to carpal joint 181; extent of wings 272 ; wing from flexure 
74; tail 24, bill along the ridge 33, along the edge of lower mandible 
44, greatest depth of upper mandible 1, depth of lower §; width of 
gape 17; tarsus 2; middle toe 23, its claw 3; outer toe 23; its claw 
33.4 ates 4 
%t; inner toe 2, its claw *#. 
