Imágenes de páginas
PDF
EPUB

CLASS IV.-continued.

"

ORDER 2. Insessores, with feet adapted only for perching, as crows, thrushes, linnets, larks, and sparrows.

[ocr errors]
[ocr errors]
[ocr errors]

"

[ocr errors]

3. Scansores, having feet specially adapted for climbing, as parrots, cuckoos, and woodpeckers.

4.

5.

6.

Rasores or Gallinaceous Birds, having short stout claws, adapted for scraping the earth in quest of food, as the common fowl, turkey, peacock, pheasant, partridge, &c. Cursores, large birds with long legs and very short wings, incapable of flight, as the ostrich, cassowary, and emu. Gralle or Grallatores, long-legged birds, with feet adapted for wading, or for walking on sand or mud, as herons, cranes, storks, snipes, and woodcocks.

7. Natatores, aquatic birds with webbed feet, as swans, geese, ducks, gulls, and penguins.

V.-Mammalia or Mammals, warm-blooded animals, viviparous, and suckling

their young.

SECT. 1. UNGUICULATA, having nails or claws.

ORDER 1. Bimana, having the fore-limbs terminated by hands, the

[ocr errors]
[ocr errors]
[ocr errors]

hinder limbs by feet. Man is the only species.

2. Quadrumana, having all the four limbs terminated by hands, and capable of grasping, as monkeys.

3. Carnaria, mammals which subsist chiefly by preying on other animals.

SUB-ORDER 1. Cheiroptera, winged mammals, all

[merged small][merged small][ocr errors]

gener

ally known by the name of bats. Insectivora, small quadrupeds having teeth adapted specially for insect prey, as shrews, moles, and hedgehogs.

3. Carnivora, quadrupeds chiefly preying on other vertebrate animals.

SECT. 1. Plantigrade, walking on the whole sole of the foot, as bears.

[ocr errors]

2. Digitigrade, walking on the toes only, as the cat, lion, tiger, &c.-dog, fox, civet, weasel.

3. Amphibia, marine animals, having feet adapted mainly for swimming, as seals, the walrus, and the sea-elephant. 4. Marsupialia, distinguished by the pouch in which the females carry their young, as kangaroos and opossums. 5. Rodentia, having the front teeth specially adapted for gnawing, as hares, rabbits, rats, mice, squirrels, and the beaver.

6. Edentata, having no teeth, or only small teeth in the back part of the jaws, as sloths, ant-eaters. SECT. 2. UNGULATA, having hoofs.

ORDER 1. Pachydermata, having a thick skin, and feeding on vegetable food, as elephants, rhinoceroses, the hippopotamus, hogs, the horse, ass, and zebra.

[ocr errors]

2.

Ruminantia, herbivorous animals, chewing the cud, as the camel, giraffe, deer, ox, buffalo, &c.-sheep, goat. SECT. 3. MUTILATA, having no hind-limbs, and the fore-limbs

modified into fins.

ORDER, Cetacea, as whales and porpoises.

CLASSIFICATION OF ANIMALS.

The student ought to make himself thoroughly familiar with the primary DIVISIONS of the animal kingdom and their distinctive characters. They are sometimes called SUB-KINGDOMS, and some of them are divided into sections, as Fishes into Osseous and Cartilaginous. They are all divided into classes, and these again into orders; which are further divided into families, and these into genera. A genus sometimes contains only one species, when it differs so much from all others as to require such a separate place; but some genera contain a great number of species, nearly resembling each other. A species consists of those individuals which are derived, or may be supposed to be derived, from a common parentage. A species is designated by the name of its genus with another word added-sometimes a name derived from the country which it inhabits, or from the name of its discoverer, often a Latin adjective, and sometimes indicative of some of its most marked characters. Thus the robin redbreast is Sylvia rubecola; Sylvia being a genus that includes many similar birds, and belonging to a family called Sylviada, which contains many genera, all of small birds, such as those known by the name of warblers, and amongst which are our finest song-birds. The relations of the terms Division, Class, Order, Family, Genus, and Species ought to be carefully observed and remembered.

We give the following as specimens of the classification of animals, selecting well-known species:

[blocks in formation]
[merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][graphic][merged small]

BOTANY.

BOTANY, from the Greek botanē, an herb, is the science which treats of plants or the Vegetable Kingdom. That part of the science which relates to the processes of plant-life is called VEGETABLE PHYSIOLOGY.

The life of a plant is very different from that of an animal. Plants and animals, however, agree in having a limited term of existence-they are born, being produced from seed; they grow, become old, and die, having during their life produced others of their own kind to replace them.

Organs-Cells.-Plants and animals agree also in being entirely composed of organs. These organs are made up of other organs, and every plant or animal ultimately consists of cells, which are at first little globules, but often become extended into very various forms. The cells of a plant have at first a thin skin like a little bladder, containing a fluid substance, in which a kind of motion is kept up. Everything in plants and animals is formed from these cells, even the wood of plants and the bones of animals. A plant or an animal grows by adding cell to cell, changes also taking place in the cells already formed. One cell is added to another, or grows from another in a determinate manner, according to the nature of each particular kind of plant or animal, and of each particular part of it. Earliest Stages of Plant-life-Germination of Seed.-A plant in the earliest stage of its existence, as it is formed in the parent plant, consists of a single cell, which is gradually developed into a seed. As the seed is matured, in all the higher kinds of plants, such as trees and floweringplants, many cells are formed in it. In a flower, we find the rudiment of the seed-vessel, containing the rudiments of the seeds, which are called ovules,1 from their resemblance to little eggs.-The rudimentary seedvessel itself is called the ovary or germen; the term ovary signifying that it contains the little eggs or ovules, and germen, a Latin word, indicating its purpose as that part of the plant from which new plants are

1 Latin ovula, a little egg.

Ъ

τα

to proceed. When the seed is placed in the ground, in favourable conditions of heat and moisture, it soon begins to germinate or sprout. Changes take place within the seed itself, new cells are formed, and through a hole in the covering of the seed, not in general easily perceptible before, a little root is sent out, which descends into the soil to seek nourishment; whilst from the same part of the seed a shoot ascends into the air, and begins to develop leaves, by which also the plant seeks nourishment; for it is sustained not only from the soil through its roots, but from the air through its leaves, the leaves being organs of nutrition as much as the roots, and equally essential to life. The part of the seed which extends downward into the soil and forms the root, is called the radicle or little root (c, fig. Fig. 72.--A bean beginning to grow, spread open. 72); the ascending part, which becomes the stem, and from which leaves, flowers, and fruit are developed, is called the plumule3 or little feather (b, fig. 72), many plants, when they first spring from the ground, having somewhat the appearance which this term suggests.

Growth and Structure of Plants.-As plants grow, the stem of many divides and subdivides into branches, but there are others in which no such division takes place, and there are many, as primroses, lilies, and hyacinths, which send up no stem, but have only flower-stalks, such as spring from the buds of other plants, arising from the crown of the root. There are also plants which have neither stem nor leaves, nor even roots, but which imbibe their nourishment through their whole surface from the air or water in which they live, as lichens, fungi, and sea-weeds. In the very lowest and simplest forms of vegetation, nothing is to be found but a mere cell, or a number of cells variously grouped together, each cell, however, appearing to be an independent plant.

Cellular Tissue and Vascular Tissue.-Some portions of all plants, and the whole of some, consist of what is called cellular tissue—that is, of mere cells variously aggregated. Cellular tissue abounds in the soft and fleshy parts of plants; and some of these are often greatly developed and increased by cultivation, so as to render the plant more useful to man. The parts of plants used for food consist mainly of cellular tissue. Cells, however, often extend in particular directions as the plant grows, or numerous cells are combined into one, some part of the separating

1 Latin germinare, to sprout.

2 From Latin radix, radicis, a root.

3 From Latin pluma, a feather.

« AnteriorContinuar »