|
constructed is the feathered wing of a bird and the membrane-covered wing of a
→OMIT
and still more so the four wings of a butterfly, the two wings of a fly, and the two
→wings with the elytra of a beetle. Bivalve shells
to open and shut, but on what a number of patterns is the hinge
from the long row of neatly interlocking teeth in a Nucula to the simple ligament of a
Seeds are disseminated by their
→minuteness,— by
their capsule being converted into a light
→envelope,— by
being embedded in pulp or flesh, formed of the most diverse parts, and rendered
as well as conspicuously coloured, so as to attract and be devoured by
→birds,— by
having hooks and grapnels of many kinds and serrated awns, so as to adhere to the fur of
by being furnished with wings and plumes, as
in shape as
→they are elegant
in structure, so as to be wafted by every breeze. I will give one other instance; for
subject
→of
the
→end being gained by the most diversified means well deserves attention. Some authors maintain that organic beings have been formed in many ways for the sake of mere variety, almost like toys in a shop, but such a view of nature is incredible. With plants having separated sexes, and with those in which, though hermaphrodites, the pollen does not spontaneously fall on the stigma, some aid is necessary for their fertilisation. With several kinds this is effected by the
→pollen-grains, which are light
and
being blown by the wind through mere chance on to the stigma; and this is the simplest plan which can well be conceived. An almost equally simple, though very different, plan occurs in many
in which a symmetrical flower secretes a few drops of nectar, and is consequently visited by insects; and these carry the pollen from the anthers to the stigma. |
| From this simple stage we may pass through an
number of contrivances, all for the same purpose and effected in essentially the same manner, but entailing changes in every part of the
→The nectar may be
stored in variously shaped receptacles, with the stamens and pistils modified in many ways, sometimes forming trap-like contrivances, and sometimes capable of neatly adapted movements through irritability or elasticity. From such structures we may advance till we come to such
→a case of extraordinary
as
lately
described by Dr. Crüger in the
Coryanthes. This orchid has
→part of its
labellum or lower lip hollowed out into a great bucket, into which drops of almost pure
continually fall from two secreting horns which stand above it; and when the bucket is half full, the water overflows by a spout on one side. The basal part of the labellum
over the bucket, and is itself hollowed out into a sort of chamber with two
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