no THE BOOK OF NATURE STUDY 



become extinct. The reptilian branch of the great genealogical 

 tree has been very severely pruned. It is outside our purpose 

 here to give an account of the general characters of Reptiles in 

 contrast to Amphibians beneath them, Birds and Mammals above 

 them. It is enough to notice that Reptiles have scaly skins, breathe 

 by lungs, are cold-blooded, and have large eggs with much yolk. 



In this connection we may venture to suggest that there 

 is little educational value in telling the pupils that " newts are 

 Amphibians, but lizards are Reptiles," i.e. in making a dogmatic 

 statement of what must at first appear to be a distinction with- 

 out a difference. It is useful, however, to get the pupils to 

 make for themselves a comparative study of two animals newt 

 and lizard which are common in some parts of the country, and 

 which can be, at the worst, bought for a small sum. Inspection 

 will show that the newt has no scales, while the lizard is covered 

 with them ; that the newt has no nails, while the lizard has them 

 strongly developed ; that the newt has a tail flattened from side 

 to side and adapted for swimming, while the lizard has a cylin- 

 drical tail which is often more decorative than useful, and so on. 



Similarly, it is very difficult for young students to believe that 

 the reptiles for the most part grovelling on the earth can be 

 related to the Birds which for the most part possess the air ; it 

 is impossible to feel convinced of this without a study of the 

 internal anatomy and the embryonic development which is 

 out of the question in school ; but it is not absurdly sanguine 

 to suppose that the school collection may include the skeletons 

 of bird and lizard, a comparison of which would show a deep 

 resemblance quite intelligible without naming a single bone ; 

 and in any case it is easy to look at a bird's foot and see that in 

 its well developed scales it harks back to a reptilian characteristic. 



British Reptiles. There are only six reptiles in Britain, 

 three lizards and three snakes. 



(1) The common lizard Lacerta vivipara. 



(2) The sand lizard Lacerta agilis. 



(3) The slow- worm Anguis fr agilis. 



(4) The adder or viper Viper a berus. 



(5) The grass snake Tropidonotus natrix. 



(6) The smooth snake Coronella lavis. 



