thrown into the ten principal quills, which are those chiefly employed in all birds to cut the air, but which in the present family are most particularly adapted for that purpose.*

The tails of the Swallows are produced, in general very stiff, and in most of the species very much forked. All the extremities of their apparatus of flight are in fact pointed, and they can turn on these points in a very singular manner, flying horizontally, or on edge, or at any intermediate angle, apparently with equal ease. The power of the tail appears to give them as much facility of ascent and descent as they have rapidity in forward flight; and as their prey is much more minute than that of even the smallest of the diurnal Accipitres, they are endowed with corresponding capacities for finding it.

It is natural to suppose that their sight is very acute. Their feet are extremely small and feeble as compared with the power of their wings, but they are not walking birds, and rarely alight upon the ground. Some of them have the feet with all the four toes to the front, or,

* Nat. Hist. and Classification of Birds. + British Cyclopædia.

very broad at the base and much depressed. The upper mandible is generally bent at the tip, and carinated. Gape extending as far back as the posterior angle of the eye. The bill itself is small and weak, and totally incapable of acting as an instrument of defence against an enemy.

Many of the species, it is almost needless to mention, form the receptacle for their eggs of mud or clay; others of extraneous matters, agglomerated by a viscous liquid, provided from a glandular apparatus peculiar to such species. The nests of some exotic species, almost entirely formed of this viscous matter, are, it is said, highly esteemed as a condiment by the Chinese and other Eastern nations.

During their migratory movements the Swallows fly in immense flocks, and they also frequently breed in large societies. They are widely dispersed over the globe, and some of them are met with in almost all climates at certain periods of the year.

The young Swallow, like the young Bee-eater, remains in the nest for some considerable period after it is hatched, which imposes upon the parents a greater degree of labour in providing food for their young than is allotted to birds of less rapid flight. How beautifully, then, is the structure and capacities of the Swallow adapted to its necessities! without showing the least symptom of weariness, it dashes through the air with the utmost rapidity during the greater portion of the day, scouring a large tract of country in a very short space of time. It is thus enabled with ease to collect ample nutriment for itself, as well as for its callow brood.

The Swift (Cypselus) is one of the fastest flying

birds, and also of long-con

tinued flight. The sternal apparatus is represented in the engraving, which shows also its full, natural size. The keel, it will be observed,

is much elevated and pointed at the anterior angle, and as no particular strength is required in the clavicles and furcal bone, on account of the easy flight of the bird, those bones are slight in comparison with the corresponding portion of the anatomy of the Falcon, which is likewise a bird of rapid flight, but one that requires great strength in these parts to support the stress which the powerful action of the muscles in its momentary rush would impose upon those bones. The sternum of the Falcon is much firmer and more developed in the anterior part; it is shorter in comparison, narrower in the posterior part than in the anterior, and the posterior angles are perforated with holes. That of the Swift has the posterior part broadest, and the angles have no holes. In the sternum of the Swift, observes Mr. Mudie, we have the maximum development of that bone as a carrying basket in the air, but still accompanied with considerable power of wing, though the Swift never rushes, either by its power of flight or by a momentum of gravitation, like the eagle. Its sternum bears up the whole under part of the body, and thus it can remain longer on the wing without fatigue than any other bird with which we are familiar.*

* Natural History of Birds.

The Swift is the largest species of British Hirundinida. Its weight is remarkably small in proportion to the extent of its wings, the latter measuring eighteen inches, while the former is scarcely an ounce.

The form of the Swift enables it to be the most rapid in its flight of all the Swallow tribe. It may be said indeed to live upon the wing. When it does alight on the ground, which is rarely indeed, it can but crawl, on account of its short tarsi. The length. of its wings also tend to keep it aloft, for they oppose themselves to its rising, which is difficult of achievement, even when attempted from moderate. elevation, and it succeeds only after more than one or two trials. It may be said in truth never to settle: willingly upon the ground. The sharp claws with which its toes are armed give it great capability for. clinging to the slightest roughness on the front of rocks or sides of towers, in the dark crevices of which it hatches and rears its young. The Swift is the latest species of the tribe that comes to our shores and the earliest to leave them, remaining amongst us only from about the middle of April until August.

Around the thousands of village towers or spires which rear their venerable heads, amid trees often coeval with themselves, in our land, these birds may very commonly be seen wheeling in the fine mornings and evenings of the pleasant months of June and July. With a sharp scream they soar above our heads, dashing about round the angles of the building with amazing velocity. There is great interest in watching them; it is while on the wing that they feed and drink, collect materials for their nest, and enjoy their existence.

From dawn of morn till twilight has almost yielded to the darkness of the night do they thus float about, except the females, which in the hidden crevice of a rock or tower brood over their eggs; the male continually flits by the nest of his mate, uttering a scream as it glides along, which the hen answers by a low murmur of satisfaction.

The Swift forms its nest of dry grass and light straws interwoven, and held together by a viscous substance; it lines it with feathers, silk, and linen threads, picked from the ground in its rapid flight. The eggs are white, and from two to four in number. When the female has sat all day, she comes forth at dusk, relieves her wearied limbs by rapid evolutions, takes a scant meal, and resumes her work of incubation.