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INTRODUCTION. 
To a large class of visitors, who desire to find in a 
zoological collection means of instruction as well as of 
amusement, a brief statement of the meaning and the 
relative value of the groups into which the animal king- 
dom is divided by naturalists will not be without inter- 
est. In order to arrive at a correct understanding of 
these, it is necessary to look at the animal world, not as 
a mere mass of living forms bearing hap-hazard resem- 
blances to each other, but as great family groups of 
beings, formed, more or less, on the same plan, varying, 
it is true, to a vast extent in the manner of its manifesta- 
tion, but all the forms of which are capable of being ar- 
ranged around great centres, each of which presents a 
somewhat different combination of structural peculi- 
arities. 
All the living forms known to science were first sys- 
tematically arranged by Linnaeus, and though the 
researches of later naturalists have at times classified 
them on other bases and in different ways, there is now 
a tendency to return, to a certain degree at least, towards 
the system of the great Swedish naturalist. 
The primary divisions now generally accepted are as 
follows : — 
The Vertebrata — possessed of a backbone, as mammals, 
birds, reptiles, batrachians, and fishes. 
The Mollusca — soft-bodied, as oysters, cuttle-fishes, and 
snails. 
The Articulata — formed of rings, as worms, centipedes, 
insects, &c. 
The Ccelenterata — as sea anemones and jelly-fishes. 
The Echinodermata — as star-fishes and sea cucumbers. 
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