830 Appendix 



Entoparasite, see Endoparasite. 



Enzyme (en' zim) (Gr. en, in; zyme, leaven), a ferment or organic catalyst se- 

 creted to bring about or hasten a reaction but which is not consumed in 

 the process. 



Epicotyl (ep'ikotl) (Gr. epi, upon; kotyle, cotyledon), portion of the embryo 

 axis above the attachment of the cotyledons to form the young stem. 



Epidermis (ep i -dur' mis) (Gr. epi, upon; derma, skin), outer layer of skin. 



Epigenesis (ep i-jen' e sis) (Gr. epi, upon; genesis, origin), doctrine that develop- 

 ment proceeds from a relatively simple germinal substance, with complexity 

 arising through the interaction of the protoplasm and the environment 

 (contrast with Preformation). 



Epiglottis (ep i -glot' is) (Gr. epi, upon; glotta, tongue), covering of the glottis 

 during swallowing. 



Epimysium (ep i -miz' i um) (Gr. epi, upon; mys, muscle), covering of a muscle. 



Epinephrine (adrenalin) (ep i -nef rin) (Gr. epi, upon; nephros, kidney), hor- 

 mone of the inner medulla of the adrenals, which are located on the kid- 

 neys. 



Epiphyte (ep' i fite) (Gr. epi, upon; phyton, plant), a plant which is physically 

 supported by another plant or from poles, wires, etc. 



Epithelium (ep i -the' li um) (Gr. epi, upon; thele, teat or nipple), membranes lin- 

 ing or covering a surface, including secreting glands. 



Equatorial plate, middle or equator of the spindle during mitosis. ^ 



Erepsin (e -rep' sin) (L. eripere, to set free), protein-splitting enzyme of the 

 intestine. 



Erythroblast (e -rith' ro blast) (Gr. erythros, red: hlastos, originate), cell from 

 which red blood cells (erythrocytes) develop. 



Erythrocyte (e -rith' ro sit) (Gr. erythros, red; kytos, cell), red blood corpuscle. 



Esophagus, see Oesophagus. 



Estivation, see Aestivation. 



Ethnology (eth-nol'oji) (Gr. ethnos, nation; logos, study), study of the charac- 

 teristics, distribution, and relationships of human races. 



Eugenics (u-jen'iks) (Gr. eugenes, well born), science of race improvement 

 through heredity. 



Eumycophyta (u mi -kof i ta) (Gr. eu, true; mykos, fungus; phyta, plants), true 

 fungi, as Phycomycetes, Ascomycetes, and Basidiomycetes. 



Eustachian tube (u-sta'shun) (Eustachio, an Italian anatomist), tube connecting 

 pharynx and middle ear. 



Evagination (e -vaj i -na' shun) (L. evageri, to go forth), outgrowing of a layer of 

 cells from a cavity. 



Evolution (ev o -lu' shun) (L. evolvo, to unroll), theory that all living organisms 

 have undergone, and do undergo, gradual changes through successive gen- 

 erations; that all living organisms are constantly changing (evolving). 



Excretion (eks -kre' shun) (Gr. ex, out; cernere, to separate), elimination of wastes. 



Excurrent (eks -kur' ent) (Gr. ex, out; currens, to run), conducting away from a 

 cavity or organ. 



Exhalant (eks -hal' ant) (Gr. ex, out: halare, to breathe), to conduct outward 

 from the interior. 



