Plin y, applied that name in a generic sense (Ornith. spec. novum, pp 47, 48) to both. Taking the hint thus afforded, Linnaeus very soon after went farthei, and, excluding the wrens, founded his genus Trochzlus for the reception of such humming-birds as were known to him. The unfortunate act of the great nomenclator cannot be set aside; and, since his time, ornithologists, with but few exceptions, have followed his example, so that nowadays humming-birds are universally recognized as forming the family Trochilidae

The relations of the Trochilzdae to other birds were for a long while very imperfectly understood. Nitzsch first drew attention to their agreement in many essential characters with the swifts, Cypselzdae, and placed the two families in one group, which he called Macrochzres, from the great length of their manual bones, or those forming the extremity of the wing. The name was perhaps not very happily chosen, for it is not the distal portion that is so much out of ordinary proportion to the size of the bird, but the proximal and median portions, which in both families are curiously dwarfed. Still the manus, in comparison with the other parts of the wing, is so long that the term M acrochires is not wholly inaccurate. The affinity of the Trochilidae and Cypselidae once pointed out, became obvious to every careful and unprejudiced investigator, and there are probably few systematists now living who refuse to admit its validity. More than this, it is confirmed by an examination of other osteological characters. The “ lines, ” as a boat-builder would say, upon which the skeleton of each form is constructed are precisely similar, only that whereas the bill is very short and the head wide in the swifts, in the humming-birds the head is narrow and the bill long-the latter developed to an extraordinary degree in some of the Trochilidae, rendering them the longest-billed birds known 1 Huxley takes these two families, together with the goat suckers (Caprimulgzdae), to form the division Cypselomorphae-one of the two into which he separated his larger group Aegithognathae. However, the most noticeable portion of the humming-bird's skeleton is the sternum, which in proportion to the size of the bird is enormously developed both longitudinally and vertically, its deep keel and posterior protraction affording abundant space for the powerful muscles which drive the wings in their rapid vibrations as the little creature poises itself over the iiowers where it finds its food? So far as is known, all humming-birds possess a protrusile tongue, in conformation peculiar among the class Aves, though to some extent similar to that member in the woodpeckers (Pzczdae)3-the “ horns ” of the hyoid apparatus upon which it is seated being greatly elongated, passing round and over the back part of the head, near the top of which they meet, and thence proceed forward, lodged in a broad and deep groove, till they terminate in front of the eyes But, unlike the tongue of the woodpeckers, that of the humming-birds consists of two cylindrical tubes, tapering towards the point, and forming two sheaths which contain the ex tensile portion, and are capable of separation, thereby facilitating the extraction of honey from the nectarines of flowers, and with it, what is of far greater importance for the b1rd's sustenance, the small insects that have been attracted to feed upon the honey 4 These, on the tongue being withdrawn into the bill, are caught by the mandibles (furnished (Voyage, iii;6), a " Todier, ” but, as Geoffr St Hilaire observes (Descr de Z'Egypte, ed. 2, xxiv. 440), is more probably a plover. Unfortunately tlle fauna of HlSp3H1Ol3 is not much better known now than in Ov1edo's days.

1 Thus Doczmastes enszfer, in which the bill is longer than both head and body together.

2 This is especially the case with the smaller species of the group, for the larger, though shooting with equal celerity from place to place, seem to Hap their wings with comparatively slow but not less powerful strokes The difference was especially observed with respect to the lar est of all humming-birds, Patagona gtgas, by Darwin. 3 The resemblance, so far as it exists, must be merely the result of analimgical function, and certainly indicates no affinity between the Zi-H11 165.

• It is probable that in various members of the Trochiladae the

structure of the tongue, and other parts correlated therewith, will be found subject to several and perhaps considerable modifications, as is the case in various members of the Pzctdae in the males of many species with fine, horny, sawlike teeth'), and swallowed in the usual way. The stomach is small, mode rately muscular, and with the inner coat slightly hardened. There seem to be no caeca. The trachea is remarkably short the bronchi beginning high up on the throat, and song-muscles are wholly wanting, as in all other Cypselomorphaefi Humming-birds comprehend the smallest members of the class Aves. The largest among them measures no more than 8% and the least 2% in. in length, for it is now admitted generally that Sloane must have been in error when he described (Voyage, ii. 308) the “ least humming-bird of ]amaica” as “ about ri in. long from the end of the bill to that of the tail ”-unless, indeed, he meant the proximal end of each. T here are, however, several species in which the tail is very much elongated, such as the Aithurus polytmus (fig 1) of ]amaica, and the remarkable Loddigesia mirabilis

of Chacha-

poyas in Peru,

which last was for

some time only

known from a

unique specimen

(Ibis, 1880, p. 152);

but “trochilidists”

in giving their

measurements do

not take these extraordinary

de-

velopments into

account. Next to their generally small

size, the best-known characteristic of the Troohilidae is the wonderful brilliancy of the plurnage of nearly all their forms, in which respect they are surpassed by no other

birds, and are only equalled by a few, as, for instance, by the Nectammzdae, or sunbirds of the tropical parts of the Old World, in popular estimation so often confounded with them.

The number of species of humming-birds

now known to exist considerably exceeds 400; and, though none departs very widely from what a morpho ogist wou d deem the typical structure o the amily, the amount of modification, within certain limits, presented by the various forms is surprising and even bewildering to the uninitiated. But the features that are ordinarily chosen by systematic ornithologists in drawing up their schemes of classification are found by the “ troch1l1d1sts, ” or special students of the Trochilidae, insufficient for the purpose of arranging these birds in groups, and characters on which genera can be ounded have to be sought in the style and coloration of plumage, as well as in the form and proportions of those parts which are most generally deemed sufficient to furnish them. Looking to the large number of species to be taken into account, convenience has demanded what science would withhold, and the genera established b the ornithologists of a preceding generation ave been broken up gy their successors into multitudinous sections the more adventurous making from 150 to 180 of such groups, the modest being content with 120 or thereabouts, but the last dignifying each of them by the title ot genus. It is of course obvious that these small divisions cannot be here considered in detail, nor would much advantage accrue by giving statistics from the works of recent trochilidlsts, such as Gould, " Mulsants and Elliot 9 It would be as unprofitable here to trace the successive steps by which the original génus Trochtlas of Linnaeus, or the two genera Polytmus 'and elltsuga of Brisson, have been split into others, or have been added V 5 These are especially observable in Rhampiiodon naemus and A ndrodon aequatoualzs.

6 P. H. Gosse (Bwds of Jamazca, p. 130) says that Mellzsuga mamma, the smallest?ecies of the family, has “ a real song "-but the like is not recorde of any other.

7 A Monograph of the Trochthdae or Humming-birds, 5 vols. imp. fol. (London, 1861, with Introduction in 8vo). ”H¢slou'e naturelle des otseaux-mouches, on colzbris, 4 vols., with supplement, imp. 4to (Lyon-Geneve-Bale, 1874-1877) ° Smtthsonian Contribulzons to Knowledge, No 17, A Classtjication and Synopses of the Trochilidae, 1 vol. imp. 4to?Washington, 1879). From The Cambridge

Natural History, vol xi,

Birds, ” by permission of

Macmillan & Co, Ltd

FIG. 1 -A zthurus

polytmus.

3