232 
PROCEEDINGS OE THE ACADEMY OE 
the head, shorter than the tarsus. Length about 19 inches, wing 7'60. Bill 
above 1*90, along gape 2*40, height at nostril *55. Tarsus 2*10; middle toe 
and claw 2*65. 
Habitat. North America, generally. 
The present species has by most authors been considered identical with the 
P. griseigena Bodd. ( [rubricollis of Latham,) of Europe. The differences, how- 
ever, as pointed out by Reinhardt, are quite tangible, and so constant as to 
render it very probable that they are of specific value. In the European bird 
the bill measures 1*50 along the culmen, 2*00 along the gape, and *50 in 
height at the nostrils ; the wing less than 7 inches. (See diagnosis for compari- 
son). In color, too, the bills differ. In P. griseigena the extreme base of the 
under mandible only is yellow, the color extending a little on the cutting edge 
of the upper mandible at base. In Holbolli nearly the whole of the under 
mandible, and the cutting edge of the upper, are yellow. 
Genus III. Sylbeocyclus Bon. 
.Podiceps, Kaup, 1829, nec Lath. 
Sylbeocyclus , Bonaparte, 1832. (Typus Pod. minor , fide G. R. Gray.) 
Tdachybaptes , Reichenbach, 1851. (Typus idem.) 
Gen. Char. Bill very short, much less than the head, scarcely more than 
half the tarsus ; very stout, little compressed, the tip obtuse ; lateral outlines 
about straight ; culmen a little concave at the nostrils, convex throughout 
the rest of its length ; gonys straight to the angle, and from angle to tip ; the 
former well defined. Wings short ; attenuation of primaries considerable ; 
abrupt on the inner web. Tarsus stout for this family, much abbreviated, 
scarcely more than three-fourths the middle toe and claw. Outer lateral toe 
abou tequal to the middle. Size small ; body full ; neck short ; without de- 
cided crests or ruffs. 
1. Sylbeocyclus dominicus (Linn.) 
Podiceps dominicus, Linn., 1766. Sylbeocyclus dominicus , — ? 
Sp. Char. Adult. — Without decided crests, but indications of them in the 
length and fulness of the feathers of the parts. Crown and occiput deep 
glossy steel blue. Sides of head, and neck all round dark ashy gray, deepest 
behind, where it is tinged with bluish. Chin variegated with ashy and white. 
Upper parts generally brownish black, with glossy greenish reflections. Pri- 
maries chocolate brown, the greater portions of the inner vanes of all. the 
whole of the four or five inner, except just at tip, together with the second- 
aries, pure white. Under parts silky white, thickly mottled with brownish 
dusky ; the abdomen uniform dusky gray. Upper mandible dusky, the lower 
mostly yellowish. 
Dimensions. Length 9*50; wing 3*60; bill above *70; along gape 1*00 ; 
tarsus 1’25 ; middle toe 1*75. 
Habitat. Central America ; Mexico ; Antillean Is. ; Gulf of California (Gam- 
bel) ; Rio Grande (eggs in Smiths. Coll.). 
[Note. — Sylbeocyclus minor, the type of the genus, is given by Nuttall as an 
inhabitant of North America ; but its existence in this country is very doubt- 
ful.] 
Subfamily PODILYMBINJE. 
Char. Bill exceedingly stout. Commissure abruptly decurved at the end. 
Nostrils broadly oval. Bare loral space broad. Feathers of the forehead with 
their shafts prolonged into stiff bristles. Tarsus not three-fourths the middle 
toe. Toes connected at base for a considerable distance ; the lobe of the hind 
toe moderate. Without decided crests or ruffs. 
Genus IV. Podilymbus Lesson. 
Podilymbus, Lesson, 1831. (Typus Colymbus podiceps , Linn.) 
Hydroha , Nuttall, 1834. 
Dasyptilus, Swainson, 1837, fide G. R. Gray. 
[April, 
