VOCABULARY. 
303 
P. 
Palmated, having a palm like that of the hand. 
Pancreas , a gland within the abdomen, just below the stomach, and 
providing a fluid to assist in digestion. 
Papillae , little projections on the surface of organs, as on the tongue, 
which are the seats of sensation. 
Papilionaceous, of or resembling butterflies. Applied to a certain tribe 
of flowers on account of their resemblance in shape to those insects. 
Pectoral, of or relating to the chest. 
Pelvis, the broad flat basin, constituting the lower part of the abdomen, 
composed principally of the broad flat bones usually called the hip and 
haunch bones. 
Peritonaeum, a membrane lining the cavity of the abdomen and giving 
a close covering to all its contents. 
Peristaltic, applied to the crawling, worm-like motion of the intestines. 
Pericardium, the bag containing the heart. 
Pericdrpium, a kind of seed vessels of plants. 
Periosteum, the membrane which adheres to, and closely invests the 
surface of bones. 
Petals, the flower leaves, or leaves of the corolla of plants. 
Pharynx, the cavity at the back part of the mouth which receives the 
food just before swallowing, and transmits it to the oesophagus. 
Phosphoric, of or resembling phosphorus. 
Pistil, the part of a flower intended to receive the pollen or fertilizing 
dust of the stamens. 
Piston , a movable cylinder in the tube of some - machines, intended to 
take off by its motion the pressure of the air, or to receive the impulse 
from steam; as in the pump and steam-engine. 
Plantule, a little plant. Applied to the part which first sprouts from the 
seed when it begins to grow. It refers to the same part with Plumule. 
Pleura, the membrane lining the chest. 
Plumule, see plantule. 
Pneumatic, of or relating to the air or wind. 
Pollen, the fertilizing dust of flowers, produced by the stamens, and falling 
upon the pistils in order to render a flower capable of producing seed 
or fruit. 
Primordial , original. 
R. 
Radicle , the little root which is first sent out by a seed when it begins to 
grow. 
Refraction, generally applied to the change of direction which takes place 
when a ray of light moves from one medium into another of a different 
density. 
Renitency, resistance. 
Retina, a very sensible and delicate membrane at the back part of the 
eye, intended to receive the images of objects like the screen of a camera 
obscura. Supposed to be an expansion of the nerve of the eye. 
Rictus , the extent of the mouth when opened widely as in gaping. 
S. 
Sanguiferous, carrying blood. 
Sensorium, the seat or centre of sensations, to which all the impressions 
made upon the external organs of sense are transmitted, and where 
they are perceived. 
