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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 during embryonic life of 
parts adapted for peculiar or 
special functions. 
Die'rr. A finger or toe. 
Di-mip'l-aTE. Half round. 
Di-q'ci-ous. (Gr. dis, two; 
oikos, house). With distinct 
sexes. 
Dip’rg-RA (Gr. dis, two; pleron, 
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-py'sts (Gr. ekdusis, casting 
off). The process of casting the 
_ skin; moulting. 
E.cHIN-0-DER'MA-TA (Gr. echinos, 
a hedgehog or urchin; hence 
applied to the sea-urchin ; and 
derma, skin). The fourth sub- 
kingdom of animals. 
E.-LA8S-MO-BRAN’CHI-1 (Gr. elasma, 
a strap; bragchia, gill) The 
sharks and rays. 
E-ta'tER. The spring or forked 
tail” of Podurans. 
E-ty’tra (Gr. elutron, a sheath). 
The fore-wings of beetles, 
serving to cover or sheathe the 
hind wings. 
Em’sry-o, The germ or young 
animal before leaving the egg 
or body of the parent, 
Enpo-suast. The primitive, 
embryonic endoderm. 
GLOSSARY. 
En'rE-ron (Gr. enteron). A gen- 
eral term applied to the diges- 
tive canal as a whole. 
E-pHEem'b-RI-NA. The order of 
net-veined insects represented 
by Ephemera, 
E’-pr-puast. The ectoderm in 
its embryo state. The ecto- 
blast. 
E-prs'o LE. Where the gastrula. 
is formed by a spreading of a 
thin layer of epiblast cells. 
over the much larger hypoblast 
cells. 
E-pts'ro-Ma. That part of the 
face of flies situated between 
the front and the Jabrum. 
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. 
Fyis-stp’a-Rowus (Lat. fissus, cleft ; 
parto, to bring forth), Ap- 
plied to aform of asexual gen- 
eration where the parent splits. 
into two parts, each part be- 
coming a new individual. 
Fa'tus. The embryo of a. 
mammal. 
Gane'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; 
parto, to bring forth). Ap- 
