Seite - 533 - in The Origin of Species

GLOSSARY 533 Cotyledons—The first or seed-leaves of plants. Crustaceans—-A class of articulated animals, having the skin of the body generally more or less hardened by the deposition of calcareous matter, breathing by means of gills. (Examples, Crab, Lobster, Shrimp, &c.) Curculio—The old generic term for the Beetles known as Weevils, charac- terized by iheir four-jointed feet, and by the head being produced into a sort of beak, upon the sides of which the antenna; are inserted. 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 characterized by having two seed leaves, by the formation of new wood between the bark and the old wood (oxogenous growth), and by the reticulation of the veins of the leaves. The parts of the flowers are generally in multiples of five. Differentiation—The separation or discrimination of parts or organs which in simpler forms of life are more or loss 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, characterized 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 mem- branous hind-wings, which constitute the true organs of flight. Embryo—The young animal undergoing development within the egg or womb. Embryology—The study of the development of the embryo. Endemic—Peculiar to a given locality. Entomostraca—A division of the class 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 smal'. size. Eocene—^The earliest of the three divisions of the Tertiary epoch of geolo- gists. Rocks of this age contain a small proportion of shells identical with species now living. Ephemero-.is 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. Felidcc—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 Grasses, the Dandelion, &c. Fatal—Of or belonging to the foetus, or embryo in course of development. Foraminifera—A class of animals of very low organization, and generally of small size, having a jelly-like body, from the surface of which deli- cate filaments can be given off and retracted for the prehension of external objects, and having a calcareous or sandy shell, usually divided into chambers, and perforated with small apertures. Fossiliferous—Containing fossils. Fossorial^\\z\-'m% a faculty of digging. The Fossorial Hymcnoptcra are a group of Wasp-like Insects, which burrow in sandy soil to make nests for tneir young. Frenum (pi. Frena)—A small band or fold of skin.