ZOOLOGY

is the study of the animal | seco! kingdom. Much of our zoological know- | the ledge is due to the labour of the Greeks, | and bat the microscope in modern times has | high given us a grasp of the subject not pre- | ence vious! tent In the lowest forms of | man aaa! as in the microscopic Ammba,| Z we find the body composed of a speck of | anen suctiting ous specidliced ert, re anaes: | cell one part, the nucleus, | rehg which controls the activity of the whole, | acco Such « unit of living matter is termed a | 6th: cell; Amopba is composed of a single cell, | a le and yet it eats, breathes, moves and has | who its being like any other animal; it thus | thrif forms no link whatever between living and | in ps non-living matter. Its mode of reproduc-| tion is peculiar; as it gets old, instead of | Fren Sying, first the nucleus and then the | soldi der of the cell divides into two | whe equal parts, and in place of one Amba | drex we have two new ones; thus Ameba only Alge dies natarally, by giving birth to two off- | deri — The higher animals, the microscope | who. begin their life as a single cell, | whe: h soon divides into two, just as; 2 eae Ble ince hl pore eons = de, and dividing again and — pro- | Na! a colony of cella which together form | 10, we ee the animal, Amoba, we note, | 210 to a Jack of all trades, one cell | The rs) — breathe, move, and so on; but! tho 1e@ vn bie! cells which forms the | res of a higher animal, division of labour | den rs; the cells that form the muscles, | libe instance, are capable of movement, | Tst hey are not concerned with digestion, | the % the cells forming the digestive | Co! m are concerned with some special | cen of the digestive proce , but have | thi: ing else todo. The animal kingdom | dec falls naturally into the following | met ps:—1. Unicellular Animals (like | at! ba), known also ag Protozoa; and | of lulticellular Animals, known also as | reti woa. The AMetazoa aro divided further | Che two great groups:—(1) the Calenterata | bro oophytes, the bodies of which are | Zul osed of only tio layers of cells, viz., | wit uter, sensory and protective, and an v. digestive layer; and(2) the Carlomata, | Swi yodies of which are composed of three | trit jore, usually many more, layers of | anc The Cealenterata are divided into | the ponges, the anemones, and the jelly | cas The Calomata are divided into (a) | ing worms, (0) echinoderms or starfish, | Th nolluses, (d) arthropods, animals with | dur ed appendages, c.g. crustaceous in- 2 and spiders, and (¢) vertebrates. | vin study of the zoology of past ages, | N.2 rm as palxontolozy, has gained in | in est sinco Darwin eee his | bat gin of Species” in 1859, We now | kill y that fish were tho first vertebrates y pear on the earth, and that they were | the seded by amphibia before the primary | Ho ical period had terminated; in the | of t udary geological period reptiles and | ean ywer mammals made their appearance, | pri towards the close, birds also; the | for r mammals have only been in exist-/ sch since the tertiary period began, whilst | par is of comparatively recent origin, 5 JOPHYTE: An animal of the sea-/ Dr none cla . See Zoology. the [s. 326]