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GLOSSARY. 



special organs for special work, 

 as the specializatiou of the 

 hand of mau from the fore- 

 foot of other mammals ; also 

 applied to the special develop- 

 ment during embryonic life of 

 parts adapted for peculiar or 

 special functions. 



Dig'it. a finger or toe. 



Di-mid'i-atb. Half round. 



Di-as'ci-ous. (Gr. dis, two; 

 oikos, house). With distinct 

 se.xes, 



Dip'tb-ra (Gr. dis, two; pieron, 

 wing). Two-winged flies ; an 

 order of insects. 



Di-VER-Tic'u-LUM. An offshoot 

 from a vessel or from the ali- 

 mentary canal. 



Duct. A tube or passage usu- 

 ally leading from glands. 



Ec-dy'sis (Gr. ekdtisis, casting 

 off). Tlie process of casting the 

 skin ; moulting. 



E-cniN-o-DEii'MA-TA (Gr. echitios, 

 a hedgehog or urchin ; hence 

 applied to the sea-urchin ; and 

 derma, skin). The fourth sub- 

 kingdom of animals. 



E lasmo-bran'ciim (Gr. elasma, 

 a strap; hragelUa, gill). The 

 sharks and rays. 



E-la'ter. Tlie spring or forked 

 " tail " of Podurans. 



E-ly'tra (Gr. elutron, a sheath). 

 Tlie fore-wings of beetles, 

 serving to cover or sheathe the 

 hind wings. 



Em'bry-o. The germ or young 

 animal before leaving the egg 

 or body of the parent. 



Endo BLAST. The primitive, 

 embryonic endoderni. 



En'te-ron (Gr. enteron). A gen- 

 eral term applied to thd diges- 

 tive canal as a whole. 



E-riiEM'E-Ei-NA. The order of 

 net-veined Insects represented 

 li,y Ephemera. 



E'-rr BLAST. The ectoderm in 

 its embryo state. The ecto- 

 blast. 



E-pib'o le. Where the gastrula 

 is foi'med by a spreading of a 

 thin layer of epiblast cells 

 over the much larger hj'poblast 

 cells. 



E-riSTO-MA. That part of the 

 face of flies situated between 

 the front and Ihe labrum. 



E qui-lat'e-ral. Having the 

 sides equal, as in Brachiopod 

 shells. 



E'qui-valvb. Applied to shells 

 like the clams and most La- 

 mellibranchs, which are com- 

 posed of two equal pieces or 

 valves. 



Ex SEii'TED. Protiuded; opposed 

 to enclosed. 



Ex-u'vi-UM. Cast-off skin. 



Fis-sir'A-ROTJS (Lat. fisstis, cleft ; 

 pario, to bring forth). Ap- 

 plied to a form of asexual gen- 

 eration where the parent splits 

 into two parts, each part be- 

 coming a new individual. 



Fos'tds. The embryo of a 

 mammal. 



Gang'li-on (Gr. gagglion, a swell- 

 ing or lump). A centre of 

 the nervous system, consisting 

 of nerve-cells and fibres. 



Gem-mir'a-rous igemmn, bud ; 

 pario, to bi ing forlh). Ap- 



