/Ceramium/ /C. rubrum/ /C. strictum/ /C. diaphanum/ The genera of an order are then placed within a cover and labeled in the same way, the legend then having the name of the order on the left and the genera on the right of the bracket, [TN: see Transcriber's Note.] thus: /Rhodymeniaceæ/, suborder /Ceramieæ/ /Callithamnion/ /Griffithsia/ /Ceramium/ When the order is a large one the genera are distributed through as many covers as may be necessary. The covers are then arranged on shelves in the regular order of their classification, and each shelf is labeled with the order it contains. Herbarium-sheets cost at retail one dollar per hundred. Genus-covers cost at retail one dollar and eighty cents per hundred. [pg019] III CLASSIFICATION The first great biological division is into kingdoms, namely, the animal kingdom and the vegetable kingdom. Then by classification the vast number of existing animals and plants are grouped so as to give each individual a definite place. By this system a beautiful order is established, which enables the student to find any particular animal or plant he may wish to study, and also to know its general characteristics from the name of the group to which it belongs. In broad generalization, objects of wide dissimilarity are recognized as belonging to the same kingdom, as do trees and grasses, or as do birds and fishes. Certain trees or grasses and certain birds or fishes have such points of resemblance that they plainly show that they belong to subdivisions. The most untutored people recognize these distinctions, but the naturalist goes further and finds points of distinction which the casual observer overlooks. The animal kingdom has a varying number of divisions, called /branches/, /subkingdoms/, or /phyla/. Some late authors have admitted twelve divisions, and have given them the name /phyla/. Each phylum is composed of a group of animals with a plan of structure which is common to themselves, but differs from that of the animals of all other phyla. The higher animals begin with the twelfth phylum, namely, the /Chordata/, or vertebrates. These animals have a spinal column, or series of vertebræ, while the lower animals, or invertebrates are without a spinal column, and depend for stability [pg020] upon muscles or coriaceous or calcareous coverings. The vertebrates are first represented in the fish-like forms. Bilateral symmetry, however, or the uniform arrangement of parts on each side of a central axis, exists in several groups which are below the vertebrates, the first pronounced example being found in worms. Groups lower than worms have their organs arranged around a central axis or radiating from it, and were once all classed as /radiates/.