trol Work

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_

[Illustration: Fig. 1; White lipped snail (Polygyra albolabris)]

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 {95} only at night,
and nearly all our American kinds live under cover of some sort.

The mollusks can be conveniently divided into three groups: those
which inhabit fresh water, those which breathe air and live on dry
land, and lastly those which are confined to the sea. The land shells,
or snails, have generally thin shells of spiral form and live upon
vegetable matter, many of them laying small eggs which look like
minute pearls. Their hiding places are under leaves in shady or moist
places, under the bark of dead trees or stumps, or under loose stone.
They creep slowly and are most active after rain. Some of our larger
kinds are an inch or two in diameter, (see Fig. 1., the white-lipped)
but from this size there are others diminishing in size to the
smallest, which are hardly larger than the head of a pin, In
collecting them the little ones may be allowed t