II. Toes 3; all in front. Toes cleft or semipalmate LIMICOLÆ.
Toes palmate. Nostrils tubular LONGIPENNES.
Nostrils not tubular PYGOPODES.
III. Toes 4; 2 in front, 2 behind. Bill cered and hooked ITTACI.
Bill neither cered nor hooked. (_Cuculi_ or _Pici_) PICARIÆ.
IV. Toes 4; 3 in front, 1 behind.
1. Toes syndactyle (_Cuculi_) PICARIÆ.
2. Toes totipalmate (all four full-webbed) STEGANOPODES.
3. Toes palmate. Bill curved up LIMICOLÆ.
Bill not curved up; lamellate LAMELLIROSTRES.
not lamellate; hallux lobate PYGOPODES.
hallux not lobate LONGIPENNES.
4. Toes lobate. Tail rudimentary PYGOPODES.
Tail perfect. A horny frontal shield ALECTORIDES.
No horny frontal shield LIMICOLÆ.
5. Toes semipalmate; joined by evident movable basal web (A).
6. Toes cleft to the base, or there immovably coherent (B).
A. Hind toe elevated above the level of the rest.
Tibiæ naked below. Nostrils perforate ALECTORIDES.
Nostrils imperforate.
Tarsi reticulate. Head bald HERODIONES.
Head feathered LIMICOLÆ.
Tarsi scutellate in front LIMICOLÆ.
Tibiæ feathered below. Nostrils perforate RAPTORES.
Nostrils imperforate.
Gape reaching below eye. (_Cypseli_) PICARIÆ.
Gape not reaching below eye GALLINÆ.
AA. Hind toe inserted on the level of the rest.
Tibiæ naked below HERODIONES.
Tibiæ feathered below. Bill cered and hooked RAPTORES.
Bill not cered.
Nasal membrane soft and tumid COLUMBÆ.
Nasal scale hard and flat GALLINÆ.
B. Hind toe elevated above the level of the rest.
Gape reaching below eye (_Cypseli_) PICARIÆ.
Gape not below eye.
First primary emarginate or about equal to 2d LIMICOLÆ.
First primary not emarginate and much shorter than 2d ALECTORIDES.
BB. Hind toe inserted on the level of the rest.
Nostrils opening beneath soft swollen membrane COLUMBÆ.
Nostrils otherwise. Bill cered and hooked RAPTORES.
Bill otherwise.
Secondaries only six (_Cypseli_) PICARIÆ.
Secondaries more than six (_a_) PASSERES.
(_a_) Primaries 10; the 1st more than 2/3 as long as the longest.
(_Clamatores_) PASSERES.
Primaries 10; the 1st not 2/3 as long as the longest.
(_Oscines_) PASSERES.
Primaries 9. (_Oscines_) PASSERES.
Recurring now to consideration of the North American _Families_ of the
foregoing higher groups, I take up the latter in the natural order in
which they have been presented, giving under head of each such group
an analysis of the North American families by which it is represented,
reiterating the caution that the characters are drawn up only with
reference to the North American genera, and are, consequently, not
necessarily or always applicable upon wider considerations. These
analyses are made as nearly natural as the state of the case permits,
but I seize upon any obvious external characters which may be
afforded, without regard to their morphological significance or
taxonomic value.