PREFACE. 



In presenting to the public a third volnmc on the 

 History of Infusorial Animalcules, I venture to express 

 a confident hope that it will prove as acceptable as the 

 Editions of 1834 and 1841. 



This Edition has been jointly prepared by J. T. Arltdge, 

 M.B. and myself. In it the classification used by Ehrenberg 

 in his great Work of 1838, has been retained; whilst 

 abstracts of the systems proposed by other naturalists have 

 been added and explained. 



The great number of new genera and species (both 

 living and fossil) here introduced, necessarily increased the 

 •/ bulk of the volume, which has been further augmented by 



doubling the number of Engravings — Graphic Illustrations 

 being indispensable to a clear comprehension of the subject. 

 These additions, however, have been made without increase 

 of cost to the subscribers who have honoured me by their 

 confidence. 



I have freely availed myself of the elaborate Avorks of 

 Ehrenberg, — the splendid monographs of Kiitzing and Ralfs, 

 as well as the valuable researches of Professors Bailey, 

 Siebold, Dujardin, Dr. Stein, Mr. Brightwcll, and others. 



