12 A ]\[AXUAL 



into four great classes, about which I shall sa}" a 

 veiy few plain words. 



The first class includes those animals termed 

 Vertebrate. 



A vertebra is the proper name for those bony 

 rings which, in great numbers, compose the back- 

 bone or spine of a man or a fish, and with which we 

 are sufficiently familiar in the pictures of skeletons, 

 or in the remains of a salmon or herring at our 

 dinner-tables. Vertebrates, then, are animals which 

 possess a back-bone, and this back-bone is the 

 channel through which the nervous centre is con- 

 tinued from the brain into the trunk, and from 

 which nerves run to the different members of the 

 animal's frame. But an anemone has no back- 

 bone — and a fish has, as well as a man, this pe- 

 culiar structure : therefore, plainly, an anemone is 

 not a fish, and a fish is more nearly related than 

 an anemone to a man. 



The second division includes animals called 

 Articulate : this word means jointed, and is applied 

 to creatures whose bodies, like the earth-worm, the 

 centipede or insects, are formed of a series of seg- 

 ments, and whose skeleton or hard parts (w4ien they 

 have any) are external. Their brain is very small, 

 and is placed on the gullet, and thence one or two 

 cords pass along the stomach, and, uniting little 

 knots of nervous matter one to each ring, are con- 

 tinued throughout the length of the creature. Thus, 



