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94 Now all owls swallow their prey whole, and in digesting this food they disgorge the skulls, bones, fur, and feathers in the form of hard dry pellets. This boy used to go out on Saturday or Sunday afternoon and bring home his pockets full of pellets, and then in the evening he would break them apart. In this way he learned exactly what the owls h4d been eating (without killing them) and he even discovered the skulls of certain field mice that naturalists had never known existed in. that region. He let the owl be his collector.

It is a good idea to keep at patrol headquarters a large sheet on the wall, where a list of the year's bird observations can be tabulated. Each time a new bird is seen, its name is added, together with the initial of the observer, and after that its various occurrences are noted opposite its name. The keenest-eyed scouts are those whose initials appear most frequently in the table. In addition, the tables will show the appearance and relative abundance of birds in a given locality. For patrols' of young boys, a plan of tacking up. a colored picture of each bird, as soon as it is thoroughly known, has been found very successful, and the result provides a way to decorate the headquarters.

Such pictures can be obtained very cheaply from the Perry Pictures Co., Boston, Mass., or the National Association of Audubon Societies, 1974 Broadway, New York City.

MOLLUSCA—Shells and Shellfish

By Dr. William Healey Dall, of the United States Geological Survey

Among the shy and retiring animals which inhabit our woods and waters, or the borders of the sea, without making themselves conspicuous to man except when he seeks the larger ones for

food, are the mollusca, usually confounded with crabs and crayfish under the popular name of "shellfish," except the few which have no external shell, which are generally called slugs. Hardly any part of the world (except deserts) is without them, but, shy as they are, it takes pretty sharp eyes to find them. Some come out of their hiding places