The Origin of Species, Charles Darwin [trending books to read .TXT] 📗

in sandy soil to make nests for their young. Frenum

(pl. Frena): A small band or fold of skin.

Fungi

(sing. Fungus): A class of cellular plants, of which Mushrooms, Toadstools, and Moulds, are familiar examples.

Furcula

The forked bone formed by the union of the collarbones in many birds, such as the common Fowl.

Gallinaceous Birds

An order of birds of which the common Fowl, Turkey, and Pheasant, are well-known examples.

Gallus

The genus of birds which includes the common Fowl.

Ganglion

A swelling or knot from which nerves are given off as from a centre.

Ganoid Fishes

Fishes covered with peculiar enamelled bony scales. Most of them are extinct.

Germinal Vesicle

A minute vesicle in the eggs of animals, from which the development of the embryo proceeds.

Glacial Period

A period of great cold and of enormous extension of ice upon the surface of the earth. It is believed that glacial periods have occurred repeatedly during the geological history of the earth, but the term is generally applied to the close of the Tertiary epoch, when nearly the whole of Europe was subjected to an arctic climate.

Gland

An organ which secretes or separates some peculiar product from the blood or sap of animals or plants.

Glottis

The opening of the windpipe into the oesophagus or gullet.

Gneiss

A rock approaching granite in composition, but more or less laminated, and really produced by the alteration of a sedimentary deposit after its consolidation.

Grallatores

The so-called wading-birds (storks, cranes, snipes, etc.), which are generally furnished with long legs, bare of feathers above the heel, and have no membranes between the toes.

Granite

A rock consisting essentially of crystals of felspar and mica in a mass of quartz.

Habitat

The locality in which a plant or animal naturally lives.

Hemiptera

An order or suborder of insects, characterised by the possession of a jointed beak or rostrum, and by having the forewings horny in the basal portion and membranous at the extremity, where they cross each other. This group includes the various species of bugs.

Hermaphrodite

Possessing the organs of both sexes.

Homology

That relation between parts which results from their development from corresponding embryonic parts, either in different animals, as in the case of the arm of man, the foreleg of a quadruped, and the wing of a bird; or in the same individual, as in the case of the fore and hind legs in quadrupeds, and the segments or rings and their appendages of which the body of a worm, a centipede, etc., is composed. The latter is called serial homology. The parts which stand in such a relation to each other are said to be homologous, and one such part or organ is called the homologue of the other. In different plants the parts of the flower are homologous, and in general these parts are regarded as homologous with leaves.

Homoptera

An order or suborder of insects having (like the Hemiptera) a jointed beak, but in which the forewings are either wholly membranous or wholly leathery. The Cicadae, froghoppers, and Aphides, are well-known examples.

Hybrid

The offspring of the union of two distinct species.

Hymenoptera

An order of insects possessing biting jaws and usually four membranous wings in which there are a few veins. Bees and wasps are familiar examples of this group.

Hypertrophied

Excessively developed.

Ichneumonidae

A family of hymenopterous insects, the members of which lay their eggs in the bodies or eggs of other insects.

Imago

The perfect (generally winged) reproductive state of an insect.

Indigenes

The aboriginal animal or vegetable inhabitants of a country or region.

Inflorescence

The mode of arrangement of the flowers of plants.

Infusoria

A class of microscopic animalcules, so called from their having originally been observed in infusions of vegetable matters. They consist of a gelatinous material enclosed in a delicate membrane, the whole or part of which is furnished with short vibrating hairs (called cilia), by means of which the animalcules swim through the water or convey the minute particles of their food to the orifice of the mouth.

Insectivorous

Feeding on insects.

Invertebrata Invertebrate Animals

Those animals which do not possess a backbone or spinal column.

Lacunae

Spaces left among the tissues in some of the lower animals and serving in place of vessels for the circulation of the fluids of the body.

Lamellated

Furnished with lamellae or little plates.

Larva

(pl. Larvae): The first condition of an insect at its issuing from the egg, when it is usually in the form of a grub, caterpillar, or maggot.

Larynx

The upper part of the windpipe opening into the gullet.

Laurentian

A group of greatly altered and very ancient rocks, which is greatly developed along the course of the St. Laurence, whence the name. It is in these that the earliest known traces of organic bodies have been found.

Leguminosae

An order of plants represented by the common peas and beans, having an irregular flower in which one petal stands up like a wing, and the stamens and pistil are enclosed in a sheath formed by two other petals. The fruit is a pod (or legume).

Lemuridae

A group of four-handed animals, distinct from the monkeys and approaching the insectivorous quadrupeds in some of their characters and habits. Its members have the nostrils curved or twisted, and a claw instead of a nail upon the first finger of the hind hands.

Lepidoptera

An order of insects, characterised by the possession of a spiral proboscis, and of four large more or less scaly wings. It includes the well-known butterflies and moths.

Littoral

Inhabiting the seashore.

Loess

A marly deposit of recent (Post-Tertiary) date, which occupies a great part of the valley of the Rhine.

Malacostraca

The higher division of the Crustacea, including the