DERMA 



98 



DEVITRIFICATION 



Derma, (der'ma). [The Greek word.]=Cutis, 



q.v. : the true skin. 

 Dermatology, (der-mat-ol'o-ji). [Gk. derma, 



skin ; logos, science.] The science of the 



nature and structure of the skin. 

 Dermatophytes, ( der - ma - tof i - tez. ) f Gk. 



derma, skin ; phyton, plant.]=Skin-plauts, 



Dermatoptera, (der-ma-top'ter-a). [Gk. derma, 

 skin ; pteron, wing.]:= Earwigs : a division 

 of Orthoptera, having membraneous wings ; 

 also called Dermaptera, and considered as 

 belonging to Coleoptera. 



Dermatozoa, (der-mat-o-zo'a). [Gk. derma, 

 skin ; zoon, animal.] Fitzinger's term for 

 Acephala, Cephalopoda, and other Mollusca. 



Dermestid, (der-mest'i-dg). [Derma, q.v.]= 

 Skin-eaters : a family of beetles, belonging 

 to Necrophaga. 



Dennis, (der'mis). [Gk. denna, skin.] The 

 real skin, below the epidermis, which bleeds 

 when cut. 



Dermopteri, ( der-mop'ter-i ). [Gk. derma, 

 skin ; pteryx, fin.] Owen's name for ver- 

 miform limbless fishes. 



Derrick crane, (der'rik). One used for 

 raising heavy weights : sometimes used for 

 those entirely above ground ; at others for 

 a crane having a spar with stays; more 

 especially for a crane mounted on a barge. 



Desert, (dez'ert). [L. desertus, forsaken.] A 

 sandy plain in which both water and vege- 

 tation are rare, probably the bed of a dried- 

 tip gulf or bay. D. birds : quails, grouse, 

 ibis, larks, &c., have the upper plumes 

 sand -coloured. D. quadrupeds: mostly 

 Band-coloured: lion, antelope, camel, kan- 

 garoo, pampas cat. 



Desiccation, (des-si-ka'shun). [L. desicco, I 

 dry up.] Drying. 



Desman, (dez'man)=Sorex mo3chatTis=:Musk 

 rat, q.v.: a small aquatic insectivorous quad- 

 ruped, which has a scent gland near tail 



Desmidiese, ( des-mi-di'e-e ) [Gk. desmos, 

 chain ; eidos, form.] A sub-division of 

 Diatomacesa ; also supposed to be animals 

 of very low organization ; very small, fresh- 

 water, green algaj, named from their cohesion 

 to each other. 



Desmids, (des'midz). \G. desmos, chain.] 

 Ciliated infusoria, v. Ciliati. 



Desmodium. [Desmos, band.] A plant belong- 

 ing to Fabaceae. 



Desmodus, (dez'mo-dns). [Gk. desmos, band ; 

 odous, tooth.] A bat; also called blood- 

 sucker. 



Desmognathus, (dez-mog'nath-us). [Gk. dfs- 

 mos, band ; gnathos, jaw.] An eft, belonging 

 to Urodela. 



Desmoncus, ( des-moivTius ). [Gk. desmos, 

 bond; ogkos, hook.] A palm-tree having 

 tendrils at the points of the leaves. 



Despretz's law, That conducted heat decreases 

 in geometrical ratio as the distance from its 

 source increases in arithmetical ratio. 



Despretz's method (1) of finding greatest 

 density of water, by noticing the lowest 

 point of a water thermometer ; (2) of 

 measuring conductivity of metals for heat. 



Desquamation, (des-kwii-ma,'shun). [L. des- 

 quamo, I peel off.]=A peeling off: a falling 

 off of scales. 



Desvauxiacese, ( dez-vo-zi-a'se-e ). [M. Des- 

 vaux.]=Bristle-worts : small herbs of New 

 Holland, &c., with sheathing leaves and 

 terminal flowers, belonging to Glumales. 



Detent, (dS-tenf). [L. detineo, I hold back.] 

 A catch to prevent a wheel from moving in 

 the wrong direction. 



Detergents, (dG-ter'jents). [L. deter geo, I rub 

 off.] Such substances as chlorine, soap, po- 

 tash leys, chloride of lime, <fec. 



Detritus, (de-tri'tus). [L. detero, I rub away.] 

 Small fragments of rocks and trees worn off 

 by rain, &c. 



Deuto, (da'to). [Gk. deutcros, second.]=Di=: 

 Bi : a prefix implying the presence of two 

 atoms of one chemical element with one 

 atom of another, as deutoxide = Dioxide ; 

 deutosulphide=Disulphide:= Bisulphide. 



Deutyl, (dutyl). A new name for ethyL 

 Deutylic=Ethylic. 



Development, (de-vel'op-ment). [F. developpcr, 

 to uncover.] 1. The third process in photo- 

 graphy, q.v. 2. A general term for the pas- 

 sage of individual plants or animals from the 

 embryo towards the adult fcondition. 3. 

 The expansion of a mathematical term into 

 a series, v. Series. 



Development : v. (2) preceding word. 

 Coniinwoi4sJ[)..'Growth=Increaseinsize with- 

 out change of form or tex- 

 ture. 



JIetaniorphosis:=: Alteration of 

 form and texture, but not of 

 size. 



Gemmation without fission= 

 Growth and metamorphosis 

 combined. 

 Discontinuous J).=Gemmation with fission. 



Gamogenesis=Sexual reproduction. 



Deviation, (de-vi-ii'shun )= Local attraction; 

 as of masses of iron in a ship which alfuct 

 the position of the ship's compass. 



Devil, (dev'il). [Dv'fol, the A.-S. word.]= 

 Didelphis ursina=Dasyurus, q.v. : an Aus- 

 tralian marsupial animal. J). monkey= 

 Cuxio=Pithecia satanas. 



Devil's : D. bit-= Helonias dioicat an Ameri- 

 can plant. D. bit scrt6ious=Scabiosa succisa. 

 D. apple = Mandrake. D. dung = Ferula 

 assafcetida. J>. d?/e=Indigofera. D. fi<j= 

 Argemone Mexicana. D. Zeo/=Urtica uren- 

 tissima: a nettle. D. coach-horse Ocypus 

 oleus : a beetle belonging to Brachyletra. 

 D. milk = Euphorbia peplus. D. wort =. 

 Plumbago scandens. D. twrnip=Bryonia. 



Devitrification, (de-vit-ri-fi-kii'shun). [L. de, 

 from; vitrum, glass; facio, I make.] A pro- 

 cess by wiiich glass is converted into porce-. 



