ETI- 



99 



EVO- 



to blanch.] The condition pro- 

 duced in plants reared in darkness 

 (bot.). 



etiolin (e'tiolin) n. [F. etioler, to 

 blanch.] A yellowish pigment 

 found in the chloroplasts of plants 

 grown in darkness (phys.). 



etiology (e'tiol'oji), see aetiology. 



euaster (uas'ter) n. [Gk. eu, good ; 

 aster, star.] An aster in which the 

 rays meet at a common centre (zool.). 



eucephalous (ukgf'alus, -sef-) a. [Gk. 

 eu, good ; kephale, head.] With 

 well-developed head ; appl. certain 

 insect larvae (zool.). 



eucone (ukon') a. [Gk. eu, good ; 

 konos, cone.] Having the crystal- 

 line cones fully developed in the 

 single elements of the compound 

 eye (zoo/.}. 



eudipleural (u'diploo'ral) a. [Gk. eu, 

 good ; dis, double ; pleuron, side.] 

 Symmetrical about a median plane ; 

 bilaterally symmetrical (zool.). 



eudoxoxne (udok'som) n. [Gk. eu, 

 well ; doxa, credit.] A monogastric 

 free-swimming stage of a Siphono- 

 phore in which there is no necto- 

 calyx (zool.). 



eugenics (ujen'iks) ;/. [Gk. eu, well ; 

 gcnos, birth.] The science dealing 

 with the improvement of stock ; 

 usually referred to betterment of 

 human race (biol.). 



euglenoid (uglen'oid) a. [Gk. eu, well ; 

 glene, pupil of eye.] Pert, or like 

 Euglena ; appl. characteristic move- 

 ment of Euglena (biol.). 



eumerism (u'me'rTzm) n. [Gk. eu, 

 well ; meros, part.] An aggrega- 

 tion of like parts (biol.). 



eumerogenesis (u'merojgn'gsis) . 

 [Gk. eu, well ; meros, part ; gig- 

 nesthai, to produce.] Segmentation 

 in which the units are similar at 

 least for a certain time (biol.). 



euplastic (uplas'tik) a. [Gk. eu, well ; 

 plastos, moulded.] Readily organ- 

 ized, easily forming a tissue (phys.). 



euryhaline (u'rihal'm) a. [Gk. eurys, 

 broad ; halinos, marine.] Appl. 

 marine animals adaptable to a wide 

 range of salinity ; cf. stenohaline 

 (biol.). 



eurypylous (u'ripl'lus) a. [Gk. eurys, 

 broad ; pyle, gate.] Wide at the 

 opening ; appl. canal system of 



Sponges in which the chambers 

 open directly into the excurrent 

 canals by wide apopyles, and re- 

 ceive the water from the incurrent 

 canals through the prosopyles 

 (zool.). 



eusporangiate (u'sporan'jlat) a. [Gk. 

 eu, well ; sporos, seed ; anggeion, 

 vessel] Having the sporogenous 

 tissue derived from the inner cell 

 that follows the periclinal division 

 of the superficial initial ; cf. lepto- 

 sporangiate (bot.). 



Eustachian(usta'kian)<z. [It. Eustachi, 

 Italian physician.] Pert, canal 

 connecting tympanic cavity with 

 pharynx (anat.). 



Eustachian valve, a rudimentary 

 valve guarding the orifice of the 

 inferior vena cava in the atrium of 

 the heart (anat.). 



eustele (u'stel) n. [Gk. eu, well ; 

 stele, pillar.] The arrangement of 

 the vascular tissue into collateral 

 bundles with the conjunctive tissue 

 between, as in a typical Dicotyledon 

 (bot.). 



eustomatous (ustom'atus) a. [Gk. eu, 

 well ; stoma, mouth.] Having a 

 distinct mouth-like opening (zool.). 



euthenics (uthfin'lks) n. [Gk. euthen- 

 ein, to thrive.] The science of the 

 betterment of the human race on 

 the side of intellect and morals ; 

 the psychological as distinct from 

 the physiological improvement, or 

 eugenics (biol.). 



euthyneurous (u'thinu'rus) a. [Gk. 

 euthus, straight ; neuron, nerve.] 

 Having the visceral loop of the 

 nervous system untwisted (zool.). 



evagination (e'vajina'shun) n. [L. e, 

 out ; vagina, sheath.] The process 

 of unsheathing, or product of this 

 process ; an outgrowth (biol.). 



evanescent (ev'anes'gnt) a. [L. evan- 

 escere, to vanish.] Disappearing 

 early ; appl. flowers which fade 

 quickly (bot.). 



eviscerate (evis'erat) v. [L. ex, out ; 

 viscera, entrails.] To disembowel ; 

 to eject the viscera, as Holothurians 

 do on capture (zool.). 



evolute (e'volut) a. [L. evolvere, to 

 unroll.] Turned back ; unfolded 

 (bot.). 



evolution (e'volu'shun) n. [L. evol- 



