276 



QL0S8ABY. 



special organs for special work, 

 as tbe specialization of the 

 hand of man 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-oe'ci-otjs. (Gr. dis, two; 

 oikos, house). With distinct 

 sexes. 



Dip'te-ba. (Gr. du, two; pteron, 

 wing). Two-winged flies ; au 

 order of insects. 



DiVER-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'si8 (Gr. ekdusis, casting 

 off). The process of casting the 

 skin ; moulting. 



Echin-o-der'ma-ta (Gr. ecMnos, 

 a hedgehog or urchin ; hence 

 applied to the sea-urchin ; and 

 derma, skin). The fourth sub- 

 kingdom of animals. 



E-LAS-MO-BBATi'CHi-i (Gr. elasma, 

 a strap; bragchia, gill). The 

 sharks and rays. 



E-la'tee. The spring or forked 

 "tail" of Podurans. 



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

 The fore-wings of beetles, 

 serving to cover or sheathe the 

 hind wings. 



Em'bryo. The germ or young 

 animal before leaving the egg 

 or body of the parent. 



En'-do-blast. The primitive, 

 embryonic endoderm. 



En'tb-kon (Gr. enterorC). A gen- 

 eral term applied to the diges- 

 tive canal as a whole. 



E-phbm'b-ei-na. The order of 

 net-veined insects represented 

 by Ephemera. 



E'-Pi-BLAST. The ectoderm in 

 ils embryo state. The ecto- 

 blast. 



E pib'o lb. Where the gastrula 

 is formed by a spreading of a 

 thin layer of epiblast cells 

 over the much larger hypoblast 

 cells. 



B-pis'to-ma. That part of the 

 face of flies situated between 

 the front and the labrum. 



E qui-lat'e-eaIi. Having tlie 

 sides equal, as in Bracliiopod 

 shells. 



E'qtii-valve. Applied to shells 

 like the clams and most La- 

 mellibranchs, which are com- 

 posed of two equal pieces or 

 valves. 



Ex-seb'ted. Protruded; opposed 

 to enclosed. 



Ex-u'vi-um. Oast-ofl skin. 



Fis-stp'a-bous (Lat. fisiU8, 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. 



Pce'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. 



GBM-Mrp'A-BOUS {gemma, bud ; 

 pario, to bring forth). Ap- 



