VI 



PREFACES. 



equally valuable disciijline — the tracing of the modifications of fomi 

 throughout less nearly allied groups . A good deal of space has, accord- 

 ingly, been devoted to this aspect of Zoology, although other aspects 

 which may excite the interest of the young student have not been 

 neglected. For example, the chapters on the Reptiles and Birds give 

 prominence to the remarkable geological history of these classes ; that 

 on the Mammals, to the correlation of form and habit in the group ; 

 while the last chapter aims at showing the connection of the various 

 subdivisions of zoological study. 



Experience alone will show, what form zoological instruction in the 

 Secondary Schools ought to assume, so as not to interfere with other 

 departments of study : the text-books on the " type-system " seemed to 

 be too advanced for the present pui'pose, and also not to afford as wide 

 an acquaintance with the forms of Animal Life as is desirable, while 

 many elementary, systematic text-books prejiared for school use do 

 not demand the actual examination of types, so necessary for the 

 formation of clear conceptions. It is hoped that the present volume 

 which endeavors to combine the advantages of both systems may prove 

 adapted to tlie purpose for which it is intended. • 



Toronto, July, 1889. 



