GLOSSARY 463 



Pedunculated. — Supported upon a stem or stalk. The pedunculated 

 oak has its acorns borne upon a footstool. 



Peloria or Pelorism. — The appearance of regularity of structure in 

 the flowers of plants which normally bear irregular flowers. 



Pelvis. — The bony arch to which the hind limbs of vertebrate animals 

 are articulated. 



Petals. — ^The leaves of the corolla, or second circle of organs in a 

 flower. They are usually of delicate texture and brightly colored. 



Phyllodineous. — Having flattened, leaf-like twigs or leaf-stalks in- 

 stead of true leaves. 



Pigment. — The coloring 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 divisi- 

 ble 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, hke 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 Sea-mats. 



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. 



