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Darwin, Charles, 1809-1882

"The Origin of Species by means of Natural Selection, 6th Edition"


CUTANEOUS.--Of or belonging to the skin.
DEGRADATION.--The wearing down of land by the action of the sea or of
meteoric agencies.
DENUDATION.--The wearing away of the surface of the land by water.
DEVONIAN SYSTEM or FORMATION.--A series of Palaeozoic rocks, including the
Old Red Sandstone.
DICOTYLEDONS, or DICOTYLEDONOUS PLANTS.--A class of plants characterised by
having two seed-leaves, by the formation of new wood between the bark and
the old wood (exogenous growth) and by the reticulation of the veins of the
leaves. The parts of the flowers are generally in multiples of five.
DIFFERENTATION.--The separation or discrimination of parts or organs which
in simpler forms of life are more or less united.
DIMORPHIC.--Having two distinct forms.--DIMORPHISM is the condition of the
appearance of the same species under two dissimilar forms.
DIOECIOUS.--Having the organs of the sexes upon distinct individuals.
DIORITE.--A peculiar form of Greenstone.
DORSAL.--Of or belonging to the back.
EDENTATA.--A peculiar order of Quadrupeds, characterised by the absence of
at least the middle incisor (front) teeth in both jaws. (Examples, the
Sloths and Armadillos.)
ELYTRA.--The hardened fore-wings of Beetles, serving as sheaths for the
membranous hind-wings, which constitute the true organs of flight.
EMBRYO.--The young animal undergoing development within the egg or womb.


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