4 PREFACE 



the good things behind. Yet the selection has 'been so 

 made as to leave untouched no considerable area of the 

 great field of Zoology which is under the control of the 

 Microscope; so that the student wjao shall have verified 

 for himself the observations here detailed, will be no 

 longer a tyro in microscopic science, and will be well 

 prepared to extend his independent researches, without 

 any other limit than that which the finite, though vast, 

 sphere of study itself presents to him. 



The staple of the work now offered to the public con- 

 sists of original observation. The author is far from 

 thinking lightly of the labors of others in this ample 

 field; but, still, it is true that, respecting very many of 

 the subjects that came under his notice, he found, in en- 

 deavoring to reproduce and verify published statements, 

 so much perplexity and difficulty that he was thrown 

 back upon himself and nature, compelled to observe de 

 novo, and to set down simply what he himself could see. 

 The ever-accumulating stock of observed and recorded 

 facts is the common property of science; and the author 

 has not scrupled to reproduce, to amplify, or to abridge 

 his own observations which have already appeared in his 

 published works and scientific memoirs, as freely as he 

 would have cited those of any other observer, in which 



