stems present no
distinction of wood, pith, and bark. The wood is disposed in
bundles, placed nearer the axis than those of the previous year, as
in palm trunks. This class answers to the Monocotyledones of
Jussieu. _Etym._, [Greek: endon], _endon_, within, and [Greek:
genesis], _genesis_, increase.

ENTOMOSTRACA. Cuvier's second section of Crustacea; so called from
their relationship to insects. _Etym._, [Greek: entoma], _entoma_,
insects.

EOCENE. A name given to the lowest division of the tertiary strata,
containing an extremely small percentage of living species amongst
its fossil shells, which indicate the first commencement or dawn of
the existing state of the animate creation. _Etym._, [Greek: eos],
_eos_, aurora or the dawn, and [Greek: kainos], _kainos_, recent.

ESCARPMENT. The abrupt face of a ridge of high land. _Etym._,
_escarper_, French, to cut steep.

ESTUARIES. Inlets of the land, which are entered both by rivers and
the tides of the sea. Thus we have the estuaries of the Thames,
Severn, Tay, &c. _Etym._, _aestus_, the tide.

EXOGENS. A class of flowering plants whose stems have bark, wood,
and pith. The bark is increased by layers deposited within the
previously formed layers and the wood of layers or rings placed
outside of those of the previous year. This class answers to the
Dicotyledones of Jussieu, and includes all common English trees
except pines, &c. (See GYMNOGENS.) _Etym._, [Greek: exo], _exo_,
outside, [Greek: genesis], _genesis_, increase.

EXPERIMENTUM CRUCIS. A decisive experiment, so called, because, like
a cross or direction-post, it directs men to true knowledge; or, as
some explain it, because it is a kind of torture whereby the nature
of the thing is extorted, as it were, by violence.

EXUVIAE. Properly speaking, the transient parts of certain animals
which they put off or lay down to assume new ones, as serpents and
caterpillars shift their skins; but in geology it refers not only to
the cast-off coverings of animals, but to fossil shells and other
remains which animals have left in the strata of the earth. _Etym._,
_exuere_, to put off or divest.

FALUNS. A French provincial name for some tertiary strata abounding
in shells in Touraine, which resemble in lithological characters the
"Crag" of Norfolk and Suffolk.

FAULT, in the language