rcle of organs in a
flower. They are usually of delicate texture and brightly coloured.

PHYLLODINEOUS.--Having flattened, leaf-like twigs or leafstalks instead
of true leaves.

PIGMENT.--The colouring material produced generally in the superficial
parts of animals. The cells secreting it are called PIGMENT-CELLS.

PINNATE.--Bearing leaflets on each side of a central stalk.

PISTILS.--The female organs of a flower, which occupy a position in the
centre of the other floral organs. The pistil is generally divisible
into the ovary or germen, the style and the stigma.

PLACENTALIA, PLACENTATA.--or PLACENTAL MAMMALS, See MAMMALIA.

PLANTIGRADES.--Quadrupeds which walk upon the whole sole of the foot,
like the bears.

PLASTIC.--Readily capable of change.

PLEISTOCENE PERIOD.--The latest portion of the Tertiary epoch.

PLUMULE (in plants).--The minute bud between the seed-leaves of
newly-germinated plants.

PLUTONIC ROCKS.--Rocks supposed to have been produced by igneous action
in the depths of the earth.

POLLEN.--The male element in flowering plants; usually a fine dust
produced by the anthers, which, by contact with the stigma effects the
fecundation of the seeds. This impregnation is brought about by means of
tubes (POLLEN-TUBES) which issue from the pollen-grains adhering to the
stigma, and penetrate through the tissues until they reach the ovary.

POLYANDROUS (flowers).--Flowers having many stamens.

POLYGAMOUS PLANTS.--Plants in which some flowers are unisexual and
others hermaphrodite. The unisexual (male and female) flowers, may be on
the same or on different plants.

POLYMORPHIC.--Presenting many forms.

POLYZOARY.--The common structure formed by the cells of the Polyzoa,
such as the well-known seamats.

PREHENSILE.--Capable of grasping.

PREPOTENT.--Having a superiority of power.

PRIMARIES.--The feathers forming the tip of the wing of a bird, and
inserted upon that part which represents the hand of man.

PROCESSES.--Projecting portions of bones, usually for the attachment of
muscles, ligaments, etc.

PROPOLIS.--A resinous material collected by the hivebees from the
opening buds of various trees.

PROTEAN.--Exceedingly variable.

PROTOZOA.--The lowest great division of the animal kingdom. These
animals are composed of a gelatinous material, and show scarcely any
trace of distinct organs. The Infusoria, Foraminifera, and sponges, with
some other forms, belong to this division.

PUPA (pl.