NATURAL HISTORY, 



CHAPTER I. 



CLASSIFICATION OF ANIMALS. 



1. THE Animal Kingdom has four grand divisions, or 

 sub-kingdoms : the Vertebrates, the Articulates, the Mol- 

 lusks, and the Radiates. 



2. The animals of the vertebrate sub-kingdom have a 

 frame-work, or skeleton of bones, inside, covered up by 

 some of the soft parts of the body. In Fig. 1 (p. 14) 

 you have the skeleton of man. You see that somewhat 

 round box of bones which contains the brain ; the col- 

 umn of bones, 24 in number, extending from this through 

 the trunk of the body ; the pelvis, consisting of a wedge- 

 shaped bone supporting this column and two broad, 

 flaring bones, m and I, on each side ; the breast-bone, 

 with the ribs extending from it to the column of bones 

 in the rear, and the collar-bone, g, stretching from it as 

 a prop to the top of the shoulder joint ; the arm-bone, i, 

 with the two bones of the forearm, n and o, and the nu- 

 merous small bones of the hand ; the thigh-bones ; the 

 bones of the leg, v and u, and those of the foot of about 

 the same number with those of the hand. 



3. That part of the skeleton in which man is like a 

 great variety of other animals is the central 



column of bones, and this is therefore taken as 

 the characteristic of the division including man 

 and these animals. In Fig. 2 you have one of 

 the bones of this column, a being its front part, 

 Fig 2* sin- an ^ ^ ^ sharp rear part, termed the spinoua 

 gie Vertebra, process. It is the row of these rear sharp parts 



