PREFACE vii 



been deemed worthy of citation. In the many cases where the 

 same authors have published several works on a given subject, only 

 the last of them is cited for example, the volume of researches 

 published recently by Mathis and Leger (473) covers the ground of 

 the earlier memoirs published by these authors, which are therefore 

 not cited ; similarly, the memoir upon amoebae by Nagler (95) 

 covers the earlier work of Hartmann and Nagler upon Amoeba 

 diploidea. Since it was quite impossible to make the bibliography 

 in any way exhaustive, the aim has been to make it, like the rest 

 of the book, introductory to the subject. It is hoped that any 

 reader who, desirous of pursuing further some special subject, 

 consults the references cited will find in them and in the further 

 works quoted in them the means of acquiring complete information 

 with regard to modern knowledge concerning all the points in 

 question. The following classes of memoirs are not cited, however, 

 in the bibliography, unless there was some special reason for doing 

 so : faunistic works, papers describing new species, and writings of 

 a polemical character. 



New memoirs on Protozoa are being published continually, so 

 rapidly, and in so many different periodicals (some of them very 

 difficult to obtain), that the author fears he may himself have 

 overlooked many such, especially of those publications which have 

 appeared very recently, while the book was in course of preparation. 

 For such omissions, some of which have already come under his 

 notice, he can but apologize, and at the same time promise that 

 they shall be rectified in future editions, if the patronage of those 

 interested in the subject enables further editions of this book to be 

 published. The present edition does not, however, profess to deal 

 with works published later than 1911. 



In order to further the object of making this book a guide to the 

 technicalities of the subject, the plan has been adopted of printing 

 in heavier black type in the index the numbers of those pages on 

 which the term cited is fulty explained, or, in the case of taxonomic 

 names, is referred to its place in the systematic classification. In 

 this way the index can be used as a glossary by anyone wishing to 

 ascertain the significance of a technical term, or, though necessarily 

 to a more limited extent, the systematic position of a genus, family, 

 or order of the Protozoa. All that is necessary for this purpose is 

 to look up the word in the index, and then to turn to the page or 

 pages indicated by black type. 



The author has, in a few cases, modified the technical terminology 

 in current use, or has made additions to it. The adjective in general 

 use relating to chromatin is " chromatic," with its various deriva- 



