GLOSSARY. 



83 



/BINS, Mineral. Cracks in rocks filled up by substances different 

 from the rock, which may either be earthy or metallic. Veins 

 are sometimes many yards wide ; and they ramify or branch off 

 into innumerable smaller parts, often as slender as threads, like 

 the veins in an animal, and hence their name. 



/ERTEBRATED ANIMALS. A great division of the animal kingdom, 

 including all those which are furnished with a back-bone, as the 

 mammalia, birds, reptiles, and fishes. The separate joints of the 

 back-bone are called vertebra, from the Latin verb verto, to turn. 



/ESICLE. A small circular inclosed space, like a little bladder. 

 Etym.y diminutive of vesica, Latin for a. bladder. 



/OLCANIC BOMBS. Volcanos throw out sometimes detached masses 

 of melted lava, which, as they fall, assume rounded forms (like 

 bomb-shells), and are often elongated into a pear shape. 



/OLCANIC Focr. The subterranean centres of action in volcanos, 

 where the heat is supposed to be in the highest degree of 

 energy. 



ZEOLITE. A family of simple minerals, including stilbite, meso- 

 type, analcime, and some others, usually found in the trap or 

 volcanic rocks. Some of the most common varieties swell or 

 boil up when exposed to the blow-pipe, and hence the name 

 of ew, 2eo, to froth, and Aifloe, lithos, stone. 



ZOOPHYTES. Corals, sponges, and other aquatic animals allied to 

 them, so called because, while they are the habitation of animals, 

 they are fixed to the ground, and have the forms of plants. 

 Elym., faov, zoon, animal, and 0i/rov, phyton, plant. 



