from other species by their proportionately strong, compressed body, as also by their large strong beak,

which is longer than the head. The foot is small, and the web but little excised; their wing is long and sabre-like; the tail but slightly forked; and the general plumage close and thick.

THE CASPIAN TERN.

The Caspian Tern (Sylochelidon Caspia) is twenty inches long, and fifty across the spread of its wings; the wing measures sixteen, and tail six inches; the feathers upon the top of the head are black, those on the sides of neck, upper back, and under surface of body, pure white; the mantle is light greyish blue; the tips of the wing-quills are darker and those of the tail-feathers lighter than the general colour of the upper parts of the plumage. The eye is brown, the beak coral-red, and the foot black. In winter the top of the head is black and white; in young birds the feathers of the back are transversely spotted with brown. The Caspian Tern inhabits Central Asia and Southern Europe; it breeds, however, exceptionally in the Island of Sylt, as well as upon some parts of the Dutch and French coasts. During the winter it appears upon the southern shores of the Mediterranean and the lower lakes of Egypt, as also in the northern parts of the Red Sea and Indian Ocean; it occurs on the west coast of Africa, but does not seem to have crossed the Atlantic. In England several specimens have been shot in Norfolk and other parts of the east coast. On the Island of Sylt it arrives towards the latter part of April, and after rearing its young, departs in August. This bird may generally be seen flying at a height of forty or fifty feet, its head, with its shining red beak, being directed downwards, and its great wings slowly waving, until from time to time it plunges headlong into the water after its prey. When in search of a resting-place it betakes itself with its companions to some rocky locality near the shore, where they all perch in a close rank, with their heads turned towards the sea, in which position they are readily mistaken for Sea Gulls. The term rapacious has been well applied to the members of this group. Fishes form their ordinary food, but they likewise devour coast and water birds, swallowing them with great ease and relish. In India they hunt eagerly after crabs, and everywhere voraciously feed upon the eggs of other birds whenever they can obtain them. Schilling tells us he has seen them fly to the breeding-places of Sea-fowl, and although at once attacked by the brooding parents, make their way to the nests quite regardless of the clamour, and help themselves without stint. Naumann and he visited a celebrated colony of this species at the northern extremity of the Island of Sylt, where they found their eggs laid upon the bare sand in little hollows, at a short distance from the water, the different broods not being more than two feet apart from each other. The eggs in shape and size much resembled those of tame Ducks. Their shells are smooth, but not shining, and their ground colour a dirty brownish white, marked with ash-grey and black; considerable difference, however, was observable even in those in the same nest. These birds begin to lay about the beginning of May; in Sylt the inhabitants regularly take the eggs, only allowing them to begin to brood eight or ten days before Midsummer. Should a man approach their nests, both male and female endeavour to defend it, and raise a terrible outcry. The young are clothed in down, of a greyish black above and white on the under surface; they soon run about, and for some days are assiduously fed with small fishes, which are brought to them by both parents.

The RIVER TERNS (Sterna) are distinguished from the preceding birds by their somewhat arched, moderately short beak, small short-toed feet, and deeply-forked tail; and by their frequent occurrence at the mouths or along the banks of rivers, or of inland streams or lakes. In size they are considerably smaller than the Caspian Terns, and their flight is much more graceful and Swallow-*like, always exciting the admiration of the beholder.