vi Preface. 



I have received invaluable assistance for several years while 

 consulting the magnificent collections of periodical and other 

 scientific literature under his care. 



Also, I cannot but refer to the Royal Society's Catalogue 

 of Scientific Publications, and to those indispensable volumes, 

 Engelmann's " Bibliotheca Historico-Naturalis," with the second 

 (Carus & Engelmann) and third (Taschenberg's " Bibliotheca 

 Zoologica ") issues. As reference books to scientific literature 

 they have never been equalled, and the test of years has proved 

 their accuracy and general reliability. A continuation of Carus & 

 Engelmann's volumes, so far as concerns Protozoa, Coelenterates, 

 and Worms, bringing the literature in part down to 1883, was 

 published in 1884 by D'Arcy W. Thompson, and this, so far as 

 it goes, will be found a serviceable guide to the allied groups of 

 the Rhizopoda. 



Finally, sincere thanks are due to Mr. F. Justen (Dulau & Co.), 

 to whose generosity and scientific sympathies I owe the publi- 

 cation of my manuscript. 



CHARLES DAVIES SHERBORN. 



540 King's Road, London, S.W. 

 August., 1888. 



