PREFATORY NOTE. 
THE collection of specimens of Mycetozoa in the 
Herbarium of the British Museum has been greatly 
increased in recent years. The additions include the large 
collection of the late C. E. Broome, bequeathed by him 
to the Museum, and that of H. W. Ravenel, purchased from 
his widow. 
It was necessary to make a critical examination of the 
whole of the materials in the Herbarium. Mr. Arthur 
Lister, who has devoted much attention to these organisms, 
was fortunately able to undertake tbis work ; and he agreed 
at the same time to prepare a monograph of the whole 
class based on this examination. 
This volume, the result of his labours, contains descrip- 
tions not only from the specimens in the Museum, but 
also from types in various pubhc and private Herbaria, and 
from his own rich collection. Mr. Lister has generously 
presented a large series of specimens to the Museum, so 
that the Herbarium uow contains types of all the species 
described by him in this monograph. 
The volume is fnlly illustrated with plates mechanically 
reproduced fi'om faithful water-colour drawings by the 
author and by his accomplished daughter, to whom in the 
Litroduction Mr. Lister acknowledges his obligations. 
WILLIAM CARHUTHERS. 
Noveviber, 1894. 
