exceptions, cannot be primarily determined by examination of adult specimens, and are based upon physiological considerations not necessarily co-ordinate with actual physical structure.
In the following scheme, without attempting to indicate positive taxonomic rank, and without committing myself finally, I present a number of higher groups into which Carinate birds may be divided, capable of approximately exact definition, and apparently of approximately equivalent taxonomic value. Points of the arrangement are freely drawn from the writings of various authors, as will be perceived by those competent to judge without special references. I am particularly indebted, however, to the late admirable and highly important work of Professor Sundevall,4 from which very many characters are directly borrowed. The arrangement, in effect, is a modification of that adopted by me in the “Key to North American Birds,” upon considerations similar to those herewith implied. The main points of difference are non-recognition of three leading groups of aerial, terrestrial, and natatorial birds,—groups without morphological basis, resting simply upon teleological modification; a general depreciation of the taxonomic value of the several groups, conformably with the considerations presented in the preceding pages of this work; abolishing of the group Grallatores; and recognition of a primary group Sphenisci.5
A. PASSERES. 6 Hallux invariably present, completely incumbent, separately movable by specialization of the flexor hallucis longus, with enlarged base and its claw larger than that of the middle digit. Neither second nor fourth toe versatile; joints of toes always 2, 3, 4, 5, from first to fourth. Wing-coverts comparatively short and few; with the exception of the least coverts upon the plica alaris, arranged in only two series, the greater of which does not reach beyond the middle of the secondary remiges.7 Rectrices twelve (with rare anomalous exceptions). Musical apparatus present in greater or less development and complexity. Palate ægithognathous. Sternum of one particular mould, single-notched. Carotid single (sinistra). Nature highly altricial and psilopædic.
a. Oscines.8 Sides of the tarsus covered in most or all of their extent with two undivided horny plates meeting behind in a sharp ridge (except in Alaudidæ; one of the plates imperfectly divided in a few other forms). Musical apparatus highly developed, consisting of several distinct pairs of syringeal muscles. Primaries nine only, or ten with the first frequently spurious, rarely over two thirds the length of the longest, never equalling the longest.
b. Clamatores.9 Sides of the tarsus covered with divided plates or scales variously arranged, its hinder edge blunt. Musical apparatus weak and imperfect, of few or incompletely distinguished syringeal muscles (as far as known). Primaries ten with rare exceptions, the first usually equalling or exceeding the rest.
B. PICARIÆ. 10 Hallux inconsiderable, weak or wanting, not always incumbent, not separately movable by distinction of a special muscle, its claw not longer than that of the middle toe unless of exceptional shape (e. g. Centropus). Second or fourth toe frequently versatile; third and fourth frequently with decreased number of joints. Wing-coverts for the most part larger and in more numerous series than in Passeres, the greater series reaching beyond the middle of the secondary quills (except in many Pici and some others). Rectrices commonly ten (eight to twelve). Primaries always ten, the first only exceptionally short (as in Pici). Musical apparatus wanting, or consisting of a muscular mass, or of not more than three pairs of syringeal muscles. Palate desmognathous or ægithognathous. Sternum of non-passerine character, its posterior border entire or doubly notched or fenestrate. Carotid single or double. Nature completely altricial, but young sometimes hatched with down11 (e. g. Caprimulgidæ).
a. Cypseli. Palate ægithognathous. Wings lengthened in their terminal portions, abbreviated basally, with the first primary not reduced. Tail of ten rectrices. Bill fissirostral or tenuirostral. Feet never zygodactyle nor syndactyle, small, weak, scarcely fitted for locomotion; hallux often elevated or lateral or reversed; front toes usually webbed at base, or with abnormal ratio of phalanges in length and number, or both. Sternum deep-keeled, usually entire or else doubly notched or perforate. Syringeal muscles not more than one pair.
b. Cuculi. Palate desmognathous. Wings not peculiar in brevity of proximal or length of distal portions, and with first primary not reduced. Tail of eight to twelve rectrices. Bill of indeterminate form, never cered; tongue not extensile. Feet variously modified by versatility or reversion of either first, second, or fourth toes, or by cohesion for a great distance of third and fourth, or by absence or rudimentary condition of first or second; often highly scansorial, rarely ambulatorial. Syringeal muscles two pairs at most.
c. Pici. Palate “exhibiting a simplification and degradation of the ægithognathous structure” (Huxley); wings bearing out this passerine affinity in the common reduction of the first primary and the restriction of the greater coverts. Tail of ten perfect rectrices and usually a supplementary pair. Rostrum hard, straight, narrow, subequal to head, with commonly extensile and vermiform but not furcate tongue. Feet highly scansorial. Fourth toe permanently reversed; basal phalanges of toes abbreviated. Sternum doubly notched. Salivary glands highly developed. Hyoidean apparatus peculiar.
C. PSITTACI. Bill enormously thick, short, high, much arched from the base, the upper mandible strongly hooked at the end, cered at base, and freely movable by complete articulation with the forehead, the under mandible with short, broad, truncate symphysis. Feet permanently zygodactyle by reversion of the fourth toe, which articulates by a double facet. Tarsi reticulate. Syrinx peculiarly constructed of three pairs of intrinsic muscles. Tongue short, thick, fleshy. Sternum entire or fenestrate. Clavicles weak, defective, or wanting. Orbit more or less completed by approach or union of postorbital process and lachrymal. Altricial; psilopædic.
D. RAPTORES. Bill usually powerful, adapted for tearing flesh, strongly decurved and hooked at the end, furnished with a cere in which the nostrils open. Feet strongly flexible, with large, sharp, much curved claws gradually narrowed from base to tip, convex on the sides, that of the second toe larger than that of the fourth toe, and the hinder not smaller than the second one. Feet never permanently zygodactyle, though fourth toe often versatile; anterior toes commonly with one basal web; hallux considerable and completely incumbent (except Cathartidæ). Legs feathered to the suffrago or beyond. Rectrices twelve (with rare exceptions); primaries sinuate or emarginate (with rare exceptions). Sternum singly or doubly notched or fenestrate. Palate desmognathous. Carotids double. Syrinx wanting or developed with only one pair of muscles. Altricial; the young being weak and helpless, yet ptilopædic, being downy at birth.
E. COLUMBÆ. Bill straight, compressed, horny at the vaulted tip, which is separated by a constriction from the soft membranous basal portion. Nostrils beneath a soft, tumid valve. Tomia of the mandibles mutually apposed. Frontal feathers sweeping in strongly convex outline across base of upper mandible. Legs feathered to the tarsus or beyond. Hallux incumbent (with few exceptions), and front toes rarely webbed at base. Tarsus with small scutella in front, or oftener reticulate, the envelope rather membranous than corneous. Head very small. Plumage without after-shafts. One pair of syringeal muscles. Sternum doubly notched, or notched and fenestrate on each side. Carotids double. Palate schizognathous. Monogamous, and highly altricial and psilopædic.
F. GALLINÆ. Bill generally short, stout, convex, with an obtuse vaulted tip, corneous except in the nasal fossa, and without constriction in its continuity. Nostrils scaled or feathered. Tomia of upper mandible overlapping. Frontal feathers forming re-entrant outline at the base of upper mandible. Legs usually feathered to the tarsus or beyond. Hallux elevated, with few exceptions (e. g. Cracidæ and
This group is insusceptible of definition. The wading birds, as usually allocated, do not possess in common one single character not also to be found in other groups, nor is the collocation of their characters peculiar.
Corresponding closely with the Linnæan and earlier Sundevallian acceptation of the term. Equivalent to the later
As remarked by Sundevall, exceptions to the diagnostic pertinence of these two characters of hind claw and wing-coverts taken together are scarcely found. For, in those non-passerine birds, as
Nearly equivalent to the Linnæan
A polymorphic group, perfectly distinguished from
