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GLOSSARY. 



special organs for special work, 

 as the specialization of the 

 hand of man from the fore- 

 foot of other mammals ; also 

 applied to the special develop- 

 ment daring embryonic life of 

 parts adapted for peculiar or 

 special functions. 



DIG'IT. A finger or toe. 



DI-MID'I-ATE. Half round. 



DI-CE'CI-OUS. (Gr. dis, two; 

 oikos, house). With distinct 

 sexes. 



DIP'TE-RA (Gr. dis, two: pteron, 

 wing). Two-winged flies ; an 

 order of insects. 



Di VER TIC'U-LTJM. 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. ekdusis. casting 

 off). The process of casting the 

 skin ; moulting. 



E CHIN-O DER'MA-TA (Gr. ecJu'nos, 

 a hedgehog or urchin ; hence 

 applied to the sea-urchin ; and 

 derma, skin). The fourth sub- 

 kingdom of animals. 



E I-AS MO BRAN'CHI-I (Gr. elasma, 

 a slrap; bmgchia, gill). The 

 sharks and rays. 



E-LA'TER. The spring or forked 

 "tail " of Podurans. 



E-LY'TRA (Gr. elutron, a sheath). 

 The 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. 



EN'-DOBLAST. The primitive, 

 embryonic eudoderm. 



EN'TE-RON (Gr. enterori). A gen- 

 eral term applied to the diges- 

 tive canal as a whole. 



E-PHEM'E-RI-NA. The order of 

 net-veined insects represented 

 by Ephemera. 



E'-Pi-BLAST. The ectoderm in 

 its embryo state. The ecto- 

 blast. 



E PIB'O LE. Where the gastrula 

 is formed by a spreading of a 

 thin layer of epiblast cells 

 over the much larger hypoblast 

 cells. 



E-PIS'TO-MA. That part of the 

 face of flies situated between 

 the front and the labrum. 



E QUI-LAT'E-RAL. Having the 

 sides equal, as in Brachiopod 

 shells. 



E'QUI-VALVE. Applied to shells 

 like the clams and most La- 

 mellibranchs, which are com- 

 posed of two equal pieces or 

 valves. 



Ex SER'TED. Protruded; opposed 

 to enclosed. 



EX-U'VI-UM. Cast-off skin. 



Fis SIP'A-ROUS (Lat. fissus, 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. 



FCE'TUS. 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-MIP'A-ROUS (gemma, bud ; 

 pario, to bring forth). Ap- 



