46 CITIZEN BIRD 



So saying, the Doctor unrolled a large sheet of draw- 

 ing-paper that hung on the wall. ''Here is a picture of 

 the Whit6-throated Sparrow, drawn so big you can see 

 it almost across the room, with all the outside parts of 

 which you must learn the names. You see the names 

 are all on the picture, too; 1 am going to make it 

 smaller, and put it in the book I will write for you, so 

 you can look at it whenever you wish. 



" It is almost dinner-time now, and you must be very 

 hungry. But now I must tell you one tiling more. 

 You know there are so many, many different kinds of 

 birds and other animals that nobody could remember 

 them unless they were classified. To classify is to put 

 things that are most alike closest together, then next 

 nearest them things that are next most alike, and to 

 keep furthest apart those things that are least alike. 

 Now it is true that all beasts, birds, snakes, lizards, 

 frogs, and fishes liave some things alike, though each 

 has some other things different from all the rest. If 

 they were not all alike in some things, we could not call 

 them all animals. One of tlie things in Avhich all the 

 animals I have named are alike is, that they all have 

 skeletons. One of the things in which all their skele- 

 tons are alike is, that they have backbones. Back- 

 bones are the chains of bones that run along the back 

 from the head to the tail. Backbones are called by 

 the Wise Men vertehrce ; animals that have backbones 

 are named Vertebrates; and animals that lack back- 

 bones are named Invertebrates.'' 



" Tell us the names of some Invertebrates, please, 

 Doctor," said Rap. 



" Well, all sorts of insects are Invertebrates, and so 



