DUR- 



82 



ECH- 



dura mater (du'ra ma'ter, door'a 

 mat'eY) n. [L. dura, hard ; mater, 

 mother.] The tough membrane 

 lining the whole cerebro-spinal 

 cavity (anat.}. 



dura spinalis, the tough membrane 

 lining the spinal canal (anat.}. 



duramen (dura'me'n) n. [L. durare, 

 to harden.] The hard, darker 

 central region of a tree-stem ; the 

 heart wood (hot.). 



dwarf male, the small three- or four- 

 celled plant formed from the andro- 

 spore of Oedogonium (hot.} ; a small, 

 usually simply formed, individual in 

 many classes of animals, either free 

 or carried by the female (zool.). 



dyad (dl'ad) n. [Gk. dyas, two.] The 

 half of a tetrad group (cyt.). 



dyaster (dl'aster) n. [Gk. dyas, two ; 

 aster, star.] " The double group of 

 chromosomes during the anaphases 

 of cell-division " (cyt.). 



dyne (din) n. [Gk. dynamis, power.] 

 The unit of force in the C.G. system 

 of physical units (phys.). 



dysmerism (dTs'merizm) . [Gk. dys, 

 hard ; meros, part.] An aggregate 

 of unlike parts (biol.). 



dysmerogenesis (dls'merqjen'esis) n. 

 [Gk. dys, hard ; meros, part ; genesis, 

 birth.] Segmentation resulting in 

 unlike parts (biol.). 



dysoxidize (disok'sidiz) v. [Gk. dys, 

 hard ; oxys, sharp.] To find difficult 

 to oxidize (phys.). 



dyspnoea (dis pnea) n. [Gk. dys, 

 hard ;pnein, to breathe.] Difficulty 

 in breathing (phys.). 



dysteleology (dis'te'le'ol'oji) n. [Gk. 

 dys, hard ; telos, end ; logos, dis- 

 course.] Haeckel's doctrine of 

 purposelessness in nature (biol.). 



dzlerzon (dzer'tson) theory, the belief 

 that the males of the honey-bee are 

 always produced from unfertilized 

 eggs (zool.}. 



ear (er) n. [A.S. eare.] The auditory 

 organ (anat.) ; the various structures 

 among invertebrates supposed to 

 have an auditory function ; the 

 specialized tufts of hair or feathers 



which are close to, or similar to an 

 external ear or pinna (zool.) ; an 

 ear-shaped structure ; the spike of 

 any cereal (bot.). 



eared (erd) n. [A.S. eare.} Having 

 external ears or pinnae ; with tufts 

 of feathers resembling ears (zool.) ; 

 having long bristles or processes, as 

 in the grains of corn, etc. (bot.). 



ebracteate (ebrak'teat), ebracteolate 

 (ebrak'teolat) a. [L. ex, from ; 

 bracteatus, covered with a gold 

 plate.] Without bracts, or without 

 bracteoles, reduced leaves on the 

 flower-stalk (bot.). 



ecalcarate (ekal'karat) a. [L. ex, 

 without ; calcar, spur.] Having no 

 spur (zool.) ; with no spur-like pro- 

 cess on the petals (bot.). 



ecardinal (ekar'dinal) a. [L. ex, 

 without ; cardo, hinge.] Having 

 no hinge ; also ecardinate (zool.). 



ecarinate (ekar'inat) a. [L. ex, with- 

 out ; carina, keel.] Not furnished 

 with a keel or keel-like ridge (bot., 

 zool.). 



ecaudate (eko'dat) a. [L. ex, without ; 

 cauda, tail.] Without a tail (zool.). 



ecblastesis (ek'blaste'sis) n. [Gk. ek, 

 out of; blastos, bud.] A prolifera- 

 tion of the main axis of an inflores- 

 cence (bot.). 



ecdemic (ekdem'ik) a. [Gk. ek, out 

 of ; demos, people.] Not native. 



ecderon (ek'deron) n. [Gk. ek, out ; 

 deros, skin.] The outer or epi- 

 dermal layer of the skin (anat.). 



ecderonic (ek'deronlk) a. [Gk. ek, 

 out ; deros, skin.] Ectodermic ; 

 epiblastic (smb.). 



ecdysis (ekdl'sis) n. [Gk. ek, out; 

 dyein, to enter.] The act of moult- 

 ing any particular cuticular layer or 

 structure (zool.). 



echinate (eVinat) a. [Gk. echinos, 

 spine.] Furnished with spines or 

 bristles (zool.). 



echinochrome (gk'inokrom', ekl'no- 

 krom) n. [Gk. echinos, spine ; 

 chroma, colour.] A colouring pig- 

 ment found in Echinoderms (zool.). 



echinoid (eVinoid, gkfnoid) a. [Gk. 

 echinos. spine.] Pert, sea-urchins 

 (zool.). 



echinopaedium (ek'fnope'dfum, ekl'no- 

 pe'dium) n. [Gk. echinos, spine ; 

 pais, child.] See dipleurula. 



