The Origin of Species by Means of Natural Selection Part 27

ENDEMIC.--Peculiar to a given locality.

ENTOMOSTRACA.--A division of the cla.s.s Crustacea, having all the segments of the body usually distinct, gills attached to the feet or organs of the mouth, and the feet fringed with fine hairs. They are generally of small size.

EOCENE.--The earliest of the three divisions of the Tertiary epoch of geologists. Rocks of this age contain a small proportion of sh.e.l.ls identical with species now living.

EPHEMEROUS INSECTS.--Insects allied to the May-fly.

FAUNA.--The totality of the animals naturally inhabiting a certain country or region, or which have lived during a given geological period.

FELIDAE.--The Cat-family.

FERAL.--Having become wild from a state of cultivation or domestication.

FLORA.--The totality of the plants growing naturally in a country, or during a given geological period.

FLORETS.--Flowers imperfectly developed in some respects, and collected into a dense spike or head, as in the Gra.s.ses, the Dandelion, etc.

FOETAL.--Of or belonging to the foetus, or embryo in course of development.

FORAMINIFERA.--A cla.s.s of animals of very low organisation and generally of small size, having a jelly-like body, from the surface of which delicate filaments can be given off and retracted for the prehension of external objects, and having a calcareous or sandy sh.e.l.l, usually divided into chambers and perforated with small apertures.

FOSSILIFEROUS.--Containing fossils.

FOSSORIAL.--Having a faculty of digging. The Fossorial Hymenoptera are a group of Wasp-like Insects, which burrow in sandy soil to make nests for their young.

FRENUM (pl. FRENA).--A small band or fold of skin.

FUNGI (sing. FUNGUS).--A cla.s.s of cellular plants, of which Mushrooms, Toadstools, and Moulds, are familiar examples.

FURCULA.--The forked bone formed by the union of the collar-bones 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 ma.s.s of quartz.

HABITAT.--The locality in which a plant or animal naturally lives.

HEMIPTERA.--An order or sub-order of insects, characterised by the possession of a jointed beak or rostrum, and by having the fore-wings h.o.r.n.y 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 s.e.xes.

h.o.m.oLOGY.--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 fore-leg 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 h.o.m.ology. The parts which stand in such a relation to each other are said to be h.o.m.ologous, and one such part or organ is called the h.o.m.ologue of the other. In different plants the parts of the flower are h.o.m.ologous, and in general these parts are regarded as h.o.m.ologous with leaves.

h.o.m.oPTERA.--An order or sub-order of insects having (like the Hemiptera) a jointed beak, but in which the fore-wings are either wholly membranous or wholly leathery, The Cicadae, frog-hoppers, 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 cla.s.s 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, or INVERTEBRATE ANIMALS.--Those animals which do not possess a backbone or spinal column.

LACUNAE.--s.p.a.ces 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.