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that the ancestral bird-stock did possess well-developed cæca, therefore all those birds which are now found without cæca must have lost them either phylogenetically or even during their embryonic development. In fact, we find in embryos of such birds as have, when adult, only very small or rudimentary cæca, that the germs of these organs are, in the embryo, just as well developed as in birds with long caca ; but these organs, in a Pigeon for instance, do not grow any further. They are in early life stopped in their development, and thus remain in a rudimentary state. Again, in all those birds which are completely devoid of cæca, their suppression is simply carried out to the extreme. We cannot therefore, as has been done sometimes, separate Birds into those with and those without cæca : this is especially wrong, as there exist many forms, which, although undoubtedly allied to each other, differ greatly in the presence or absence of these organs. If we want to use the cæca as a differentiating character, we must consider their quality, and enquire whether those organs are functional and well developed, or are they now without function ? Consequently birds with rudimentary cæca have to be grouped together with those which have no cæca, although the ancestors of both had functional cæca ; and since we know that these organs stand in close correlation with the nature of the food, we are enabled to weigh their taxonomic value. Hence it is probable that the Owls are related to the cæcapossessing Nightjars, and that the cæcaless Macrochires (like Swifts) are a recent offshoot of the latter, while it is impossible to assume that the Owls are descendants of the Diurnal Birds-of-Prey.

The modifications of the Carotid Arteries have enabled Prof. Fuerbringer to draw a very ingenious and valid conclusion as to the probable original centre of the Parrots. While the Australian, Oriental, and African Parrots exhibit almost every possible modification of these arteries, from the most primitive to the most specialised conditions, the American Parrots possess only the right deep carotis and a left superficial carotis, an arrangement which is a decidedly recent, not primary feature. Hence the conclusion that the American Parrots are a branch of the Palæotropical stem ; but however fascinating such speculations are, we must not forget that they hardly ever amount to definite proofs.

Supposing we divide Birds into two classes (A and B), according to the presence or absence of the AMBIENS muscle. As a second differentiating character let us take the functional or fully developed (a) and the absent or functionless state of the CÆCA (b); and as a third character the presence (a) or absence (B) of an AFTERSHAFT. Then using the ambiens as the principal, and the aftershaft as the tertiary differentiating feature, and indicating presence or absence by the signs + and – respectively, we get the following eight divisions :

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Thus the Owls in this arrangement approach nearest to the Auks and Grebes, while the Parrots, owing to their variable ambiens muscle, are grouped either with the Accipitres, or with the Swifts and Humming-birds. This is obviously unsatisfactory, perhaps owing to the value of the ambiens muscle being overrated. Let us next use the aftershaft as the principal, the ambiens as the secondary determining character, and the cæca as the third. Then the Psittaci approach the Gallinaceous birds and also the Auks and Grebes, while the Owls verge into the neighbourhood of Pigeons, Herons, and Passerine birds. Again, by using the cæca as the principal, and the ambiens as the secondary feature, Psittaci, Accipitres, and Columbæ, Owls, Auks, and Grebes are once more thrown together. The same or very similar arrangements result from a combination of the cæca with the oil-gland, or of the ambiens and cæca with the conditions of the palatal bones. But these persistent coincidences will never induce us to look upon them as indicating relationship between Owls, Auks, and Grebes, because this conclusion would be obviously wrong! How does the question stand with regard to other combinations, when · we cannot at a glance discern a glaring error ? When, e.g. according to the muscles of the thigh, leaving out the ambiens, Striges, Accipitres, and Cypselidæ stand closely together? Is this a mere coincidence or does a deeper meaning underlie this Trias ? It is obviously not due to a superior taxonomic value of Garrod's myological formulæ, because application of the same principle throws Nightjars, Storks, and Parrots together.

It is hopeless to attempt to arrive at a natural classification of Birds by a mechanical arrangement of even a great number of alleged leading characters. More may be expected from the combination of various taxonomic arrangements, each of which has been based upon a single organic system without reference to other organs. Of course every one of such one-sided attempts will occasionally shew a rather perplexing face, but each of them will bring to light some unexpected points of resemblance between certain groups; and, while restricting ourselves to one organic system, we are more likely to understand which points are given to modifications through mode of life, food, habit, and surroundings, and which remain least affected, and therefore are indicative of relationship. Let us then combine the several one-sided arrangements. They will each of them contribute something good or certain, and thus help to settle the great question. Reasoning from a broad basis of facts will do the rest.

ANHIMA or ANHINGA, see SNAKE-BIRD.

ANI, according to Marcgrave (Hist. Rer. Nat. Brasiliæ, p. 193), the Brazilian name of what is the Crotophaga major of modern ornithologists, who have ignorantly misapplied Linnæus's designation, C. ani, to its smaller congener, an inhabitant of the Antilles and part of the Spanish Main. This latter is known to most of the English-speaking people of the West Indies as the Black Witch or Savanna Blackbird. The genus Crotophaga is one of the most remarkable forms of the Cuculida (CUCKOW) of the New World.

ANISODACTYLI, Vieillot's name, in 1816 (Analyse, p. 29), for the second tribe of his second Order, comprehending all the PASSERES of Linnæus and such of the latter's PICÆ as had not two toes before and two behind. By some later authors the name has been restricted to the genera which are not ZYGODACTYLI and are yet placed among the SCANSORES.

ANKLE-JOINT. The true ankle-joint is a Mammalian feature, being the articulation of the tibia with the astragalus, and therefore a tibio-tarsal joint. In Birds the so-called ankle-joint is an intertarsal joint, because the proximal tarsal bones, of which the astragalus is one, are fused with the end of the tibia, and the distal tarsal are fused with the metatarsal bones (see SKELETON).

ANOMALOGONATÆ, the second of the two subclasses, the other being called HOMALOGONATÆ, into which Garrod at one time divided Birds, according as they possessed an AMBIENS muscle or not (Proc. Zool. Soc. 1874, pp. 116-118). In the Homalogonatous or "typically-kneed” birds “the ambiens runs in the tendon of the knee,” though there are some of them in which it is absent; but “there cannot be any Anomalogonatous birds in which it is present." For the groups which are contained in these categories, see INTRODUCTION.

ANSERES, the third Order of the Class Aves according to the system of Linnæus, comprising all the Web-footed Birds known to

MALOGONAT-Ez hey possessed, 29. In th

him except Phænicopterus (FLAMINGO) and Recurvirostra (AVOSET). If the term be used at the present day, it must be limited to the Geese and their allies.

ANT-THRUSH, Latham’s rendering in 1783 (Gen. Synops. ii. p. 87) of Buffon's Fourmilier proprement dit (IIist. Nat. Ois. iv. p. 473), a bird figured by Daubenton (Pl. enl. 700, fig. 1) as the Fourmillier de Cayenne, the Formicarius torquatus of Boddaert in 1783, the Turdus formicarius of Gmelin in 1788, and the Rhopotrope torquata of modern systematists; for, though it should be logically recognized as the type of the genus Formicarius, Prof. Cabanis in 1847 (Orn. Notiz. p. 227), misled probably by G. R. Gray, removed it to one of his own making. This little bird, not so big as a Skylark, is very beautiful, notwithstanding its curious figure, with a disproportionately long bill, short tail, and strong legs, and absence of bright coloration, for the black, rich brown, sienna, buff, grey and white which its plumage presents, are most harmoniously contrasted or blended. It is a native of the northern parts of South America, and Buffon received it from Cayenne through Manoncour, the little we know of its habits being due to the latter. It is a mark of Buffon's insight that he at once recognized in this species, and several others allied to it, obtained from the same source, a perfectly distinct group of birds which he designated Fourmiliers from their feeding (as he was told) chiefly on Ants. 1 The systematists of his day, Boddaert and Hermann excepted, were not so perceptive, and referred these birds to the Thrushes or some of them to the Shrikes. Their distinctness was at last recognized, and they were duly regarded as forming a Family, Formicariida, which is now known to contain more than 250 species, and by Mr. Sclater (Cat. B. Br. Mus. xv. pp. 176-328) in 1890 has been divided into 3 subfamilies Thumnophilina, often known as “Bush-Shrikes," containing 10 genera and at least 80 species ; Formicariinx, the true Ant-Thrushes, including in them the Formicivorina, by Swainson ? called “ Ant-Wrens” (200l. Journ. ii. p. 146), that Mr. Sclater had formerly (P. 2. S. 1858, pp. 232-254) recognized, and thus enlarging the Formicariinæ so as to comprise 18 genera and more than 130 species; while the third subfamily Grallariinæ includes 5 genera and over 30 species. In

1 Mr. Bates (Nat. Amazon, ii. p. 357) says that the first signal given to the pedestrian of meeting with a train of Foraging Ants (Ecilon) is the twittering and restless movement of small flocks of Ant-Thrushes in the forest, and that if he disregards their warning he is sure to be attacked by the ferocious insects.

? Swainson did not know that his genus Formicivora had been anticipated by Temminck, who in 1807 (Cat. du Cab. p. 92) used the name Formicivorus, in a sense equivalent to Boddaert's Formicarius. The group separated by Swainson was in 1827 called by Gloger Eriodora, which name therefore apparently ought to be used for it.

reality but few of these birds have an outward resemblance to Shrikes, Thrushes, or Wrens, and all belong to quite a different division of PASSERES. In 1847 Johannes Müller and Prof. Cabanis justly placed them among their CLAMATORES, and subsequently Garrod shewed their Mesomyodian structure. The Formicariidæ are one of the most characteristic Families of the Neotropical Region, abounding in the forest-districts of its middle portion, becoming less numerous in Central America, and still scarcer in the southern parts, only just reaching the plains of La Plata. They are mostly small birds of sober hue, some not bigger than Wrens; but members of the Genera Batara and Grallaria attain the stature of a Jay. The

group to which the name "Ant-Thrush " has also been applied. As is the case with most South-American birds, scarcely anything is known of their habits. The large genus Thamnophilus, containing upwards of 50 species, is one of the most important of the so-called “Bush-Shrikes," and many of its members are remarkable for the sexual diversity in plumage, that of the cocks being black or black banded with white, while that of the hens is rufous; but in some other groups the black or black-and-white plumage is common to both sexes. Of this genus

ANT-THRUSH (Thamnophilus).

(After Swainson.) several species inhabit British Guiana, at least three occur in Trinidad, and one is found in Tobago, where it is known as the Qua-qua or Cata-bird (Ann. N. H. xx. p. 331), their presence in these two islands offering one of the many strong proofs of their fauna belonging to that of continental South America, since no member of the Family is found in the Antilles proper.

AORTA (adj. aortic), the principal ARTERY from which arise the blood-vessels supplying the trunk, hind limbs, and viscera below or behind the heart (see VASCULAR SYSTEM).

APTERYX, see Kiwi.
ARCHÆOPTERYX, see Fossil BIRDS.

AREND, the Dutch for Eagle, but used by the colonists in South Africa for the Bearded Vulture or LÄMMERGEYER.

ARGALA, Hindoo Hargitasaid by Yule to be the kỹda of Ælian (xvi. 4)—a name of the ADJUTANT.

ARGUS or ARGUS-PHEASANT, the name originally applied in ornithology to the extraordinary and beautiful birds of the Malay Peninsula, Siam, and Borneo, which are not distantly related to the PEACOCK; but by English sportsmen in India commonly

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