THE COMMON FROG. [chap. 



If the Frog was only known by certain fossil 

 remains, it would be considered one of the most 

 anomalous of animals. 



Many persons are accustomed to make much of 

 the distinctive peculiarities of the human frame. In 

 fact, however, Man's bodily structure is far less ex- 

 ceptional in the animal series, is far less peculiar and 

 isolated than that which is common to Frogs and 

 Toads. 



The number and nature of both the closer and 

 the more remote allies of the Frog ; its distribution 

 both as to space and as to time ; its relationships 

 whether of analogy or affinity^ to very different 

 animals; its bony framework; its muscles and nerves; 

 its brain and sense organs ; its respiratory and 

 excretory structures ; its various changes from the 

 ^^% to maturity, together with peculiarities of habit 

 in allied forms, — are all matters which will well repay 

 a little attentive consideration. 



Indeed it is probable that no other existing animal 

 is more replete with scientific interest of the highest 

 kind, than is the Frog. 



About it are gathered biological^ questions which 

 bear upon the origin of species, and upon the course 

 and mode of organic development, as well as other 

 speculative problems to which answers are as yet far 

 to seek. 



^ Analogous relationship refers to the uses to which parts are pu^. 

 Relationship of affinity refers either to such a relationship as that of 

 kindred or to an ideal affinity reposing on similarities of structure. 



2 iiiological questions are questions referring to living beings, 

 *' Biology" being the science which treats of all living things, including 

 both plaiits and animals. 



