AN INTRODUCTION TO ANIMAL BIOLOGY 65 



which are very similar in structure. This similarity is be- 

 lieved to indicate close relationship, and hence the animals 

 which are most like frogs are said to be relatives or allies. 



The nearest allies of frogs (that is, the animals most like 

 them) are the toads. Next nearest are the animals known as 

 newts and salamanders. Toads, frogs, newts, salamanders, 

 and similar animals together constitute a group of animals 

 which have closer resemblances to each other than to any 

 fishes, reptiles, or other backboned animals. To this group 

 the term Amphibia is applied ; and we may speak of frogs 

 and salamanders as amphibians, just as we say that salmon 

 and perch are fishes. 



The various kinds of common frogs are known by double 

 scientific names, such as Rana catesbiana (bull-frog), Rana 

 sylvatica (brown wood-frog), Rana virescens (the leopard 

 frog), and so on for many other kinds. The common Ameri- 

 can toad is scientifically known as Bufo Americanus, while 

 certain little tree-toads are specimens of Hyla versicolor. 



The system employed in giving scientific names to animals 

 and plants will be explained in Chapter VII. 



The Life-Activities of a Plant. Having now studied in 

 considerable detail the structure and life-activities of an 

 animal which illustrates in a general way the life of all 

 animals, it will be interesting to make a parallel study of a 

 plant in order to see how it performs the functions of moving, 

 breathing, using food, reproducing, etc., life-activitiee 

 wh\ch have been pointed out in 29 as occurring in both 

 animals and plants. Such a study is presented in the next 

 chapter. 



