AUTHOR'S PBEFACE. 



The present volume, dealing with Sporozoa, follows the same 

 plan as the author's volume on Ciliophora, published two years 

 ago. The group Sporozoa includes numerous organisms, 

 all of which are parasitic in hosts belonging to a number 

 of different phyla of the Animal Kingdom. Several of these 

 organisms are responsible for producing disease in man and 

 domestic animals, and consequently come within the ken of 

 the medical and veterinary workers : but there are numerous 

 others which parasitize animals such as earthworms, poly- 

 chsetes, crustaceans, insects, myriopods, arachnids, moUuscs, 

 fishes, amphibians, reptiles, birds, etc., and, though causing 

 damage to various tissues of the host, are on the whole tolerated 

 by them . To the student of Protozoa all are equally interesting 

 and it is his province to study them as animals, and name and 

 classify them. The medical and veterinary workers will 

 find in this volume the correct zoological position and nomen- 

 clature of the pathogenic organisms they study. With 

 regard to the nomenclature, the synonyms recorded under 

 each species will serve to indicate the extent to which opinion 

 has in the past varied with regard to the systematic position 

 of the particular organisms. In a few cases the reader may 

 feel disposed to differ from me, but in such cases he will find 

 the argument or the authorities on which I have relied 

 clearly stated, and if, after considering them, the reader still 

 differs, he is welcome to do so. 



The most approved and up-to-date system of classification 

 has been followed, and in the Identification Tables of Families 

 I have included those families which are at present not known 



FEB -9 



