GLOSSARY 333 



pharynx, far'ingks (Gr. pharungx, the gullet or windpipe), a part of the 



alimentary canal between the mouth and oesophagus. 



photosynthesis, fo to sin' the sis (Gr. phos, light; synthesis, a putting to- 

 gether), the manufacture of starch by chlorophyll in the presence of 



light. 

 phototropism, fotofropizm (Gr. phos, light ; trope, a turning), reaction to 



light. 

 phylogeny, fl loj'eni (Gx.phylon, a tribe; gennao, I produce), the study of 



the ancestral history of organisms. 

 phylum, fl'lum (Gr. phylon, a tribe), any primary division of the animal or 



vegetable kingdom, 

 physiology, fiz i ol'oji (Gr. phusis, nature; logos, discourse), the study of 



the functions of living things. 

 plasma, plas'ma (Gr. plasma, a thing formed), protoplasm ; the liquid part 



of the blood, 

 plasm osome, plas'mdzom (Gr. plasma, a thing formed ; soma, body), a 



nuclear constituent distinguished by its affinity for plasma-stains. 

 plastid, plas 'tid (Gr. plasso, I form or mold), a permanent cell organ other 



than nucleus and centrosome. 



pleopod, pie' o pod (Gt.pleein, swim; pous, foot), one of the abdominal ap- 

 pendages of a crustacean ; swimmeret. 

 polar bodies, two minute cells segmented off from the ovum before union of 



the germ nuclei. 

 pollen, pol'en (L. pollen, fine flour), the fertilizing powder contained in the 



anthers of flowers. 

 pronucleus, pronu'klsus (L. pro, before; nucleus}, a male or female 



nucleus during fertilization. 



prophase, pro'fdz (Gr. pro, before), the early period of mitosis. 

 propolis, prop 'o Us (Gr. pro, before ; polls, city), a substance collected by 



bees to stop up crevices in the hive, 

 prostomium, prosto'mium (Gr.pro, before ; stoma, mouth), the region in 



front of the mouth. 

 proteid, pro'le id (Gr. protos, first), a nitrogenous substance found in the 



bodies of plants and animals, 

 proteus, pro'te us (a sea god who had the power of assuming different 



shapes), the specific name of an ameba. 

 protoplasm, pro'toplazm (Gr. protos, first; plasma, a thing formed), the 



essential substance of the bodies of organisms. 

 protopodite,/r<7/0/'<?^7 (Gr. protos, first; pous, a foot), the basal segment 



of a crustacean appendage. 

 Protozoa, pro to zd 1 'a (Gr. protos, first; zoon, animal), a phylum of animals 



(see p. 80). 



