GLOSSAEY. 313 



Gland. — An organ wliicli 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 comiDosition, but more or 



less laminated, and really produced by the alteration of a 



sedimentary deposit after its consolidation. 

 Geallatores. — The so-called Wading-birds (Storks, Cranes, Snipes, 



&c.), 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 sub-order of Insects, characterised by the 

 possession of a jointed beak or rostrum, and by having the fore- 

 wings 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 lesults from their 

 development from corresponding embryunic parts, either in 

 - different animals, as in the case of the arm of nian, the fore-leg 

 of a quadruped, and the wing of a bird ; or in the same in- 

 dividual, as in the cat^e 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, &c., is composed. The latter is 

 called serial homology. The parts w hich 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 sub-order of Insects having (like the 

 Hemiptera) a jointed beak, but in which the fore-wings are 

 either whtJly membranous or wholly leathery. The Cicadx, 

 Frog-hoppers, and Aphides, are well-known examples. 



Hybrid. — The offspring of the union of two distinct species. 



Hymenoptera. — An order of Insects posscbsing biting jaws and 

 usually four membranous wings in which there are a lew veins. 

 Bees and Wasps are lamiliar examples of this group. 



Hypertrophied. — Excessively developed. 



