GLOSSARY. 485 



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 animalf 

 are articulated. 



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

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



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

 stead of true leaves. 



Pigment. — The coloring material produced generally in the supe,* 

 ficial 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 Mam- 

 malia. 



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-knov/n 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. 



Processes. — Projecting portions of borss, usually for the attachment 

 of muscles, ligaments, etc. 



Propolis. — A resinous material collected by the Hive-Bees 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, Foramini- 

 fera and Sponges, with some other forms, belong to this division. 



Pupa (pi. Pup^e). — The second stage in the development of an In- 

 • sect, from which it emerges in the perfect (winged) reproductive 

 form. In most insects the pupal stage i, a passed in perfect repose* 

 The chrysalis is the pupal state of Butterflies. 



