The partial migrants, which form the third class, are rather more puzzling in their movements, for among them we find birds whose motives for wandering are very diverse. Some are unwilling slaves--_i. e._, they get mixed up in the big flights of true migratory birds, and are irresistibly hurried along with them; such are the rooks, starlings, robins, etc., which are so frequently seen in Heligoland in the midst of a flock of swallows, warblers, and other genuine migrants. Another lot of these partial migrants are those which, perhaps, most justly deserve this name; viz., such birds as larks, pipits, titmice, etc., which, although resident with us all the year round, at times greatly diminish in numbers, owing to more than half the individuals changing their abode. For instance, those which breed in Scotland and England wander in the winter over to France, but, unlike the true migrant, always leave some of their number behind.--_Walter Rothschild, The Nineteenth Century._ HOW BIRDS CARRY SEEDS. Dr. Howard, the new secretary of the American Association for the Advancement of Science, writing of the manner in which seeds are carried to a great distance by birds, recited an experiment of Darwin, which had a curious result. Adhering to the leg of a wounded partridge, Darwin found a ball of earth weighing six and a half ounces. From the seeds contained in this ball he raised thirty-two plants belonging to five distinct species. THE SHIP OF THE DESERT. The pack camel travels very slowly, and until you are sufficiently reconciled to the motion to be able to doze on its back, you are constantly tempted to get off and walk. If you want speed, you must buy a racing camel. This seems to belong to a different creation. It is much taller, more alert and more intelligent. It can accomplish 150 miles in sixteen hours without undue effort, and, in the matter of price, compares with the pack camel as the thoroughbred does with the cab horse. THE SNAPPING-TURTLE. By reason of the ferocity of disposition of this curious animal, the snapping-turtle (_Chelydra serpentina_) is rather formidable, not only to the smaller creatures which inhabit the same localities, but also to man, its bite causing very severe wounds. It is found in America from Canada to Ecuador, and there are few localities where it is not met with frequently. Swimmers in small lakes are sometimes attacked by it, the habits of the animal both in the water and on land being the same. It is bold as well as fierce, often suffering itself to be lifted from the ground by the object which it has grasped rather than to let go its hold. If attacked, the reptile's long reach and strong jaws enable it to defeat any ordinary foe. The elongated tail of the snapping-turtle has given rise to the popular name, alligator turtle and, being appended to the small, comparatively thin shell, giving an elongated appearance to the body, the specific name _serpentina_ resulted.