vi PREFACE. 



entirely yellow, some banded with broad streaks of alternately 

 velvety black and silvery white ; while the eye of the toad is a 

 living gem of beauty. When, however, we come to look closer 

 to watch their habits to note their instincts or, by the 

 use of the microscope, to lay open to our view some of the 

 details of their organization then indeed are we lost in wonder 

 and amaze at the vastness of creation, which, even in one 

 little, apparently insignificant animal, presents to our eyes mar- 

 vels marvels which increase in number and beauty as our 

 power for perceiving them increases. 



MERTON COLLEGE, OXFORD, 

 December 10, 1852. 



