478 GLOSSARY. 



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 (exogenous 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 less united. 



Dimorphic. — Having two distinct forms — Dimorphism is the con- 

 dition of the appearance of the same species under two dissimilar 

 forms. 



Dicecious. — Having the organs of the sexes upon distinct indi- 

 viduals. 



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 membraneous 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 small size. 

 Eocene. — The earliest of the three divisions of the Tertiary epoch of 



geologists. Rocks of this age contain a small proportion of shells 



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. 



Felid js. — The Cat-family. 



Feral, — Having become wild from a state of cultivation or domesti- 

 cation. 



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 col- 

 lected into a dense spike or head, as in the Grasses, the Dande- 

 lion, etc. 



Fcetal. — Of or belonging to the foetus, or embryo in course of devel- 

 opment. 



Foraminifera. — A class of animals of very low organization 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 

 shell, usually divided into chambers and perforated with small 

 apertures. 



Fossiliferous. — Containing fossils. 



