( ix ) 
PREFACE. 
The “ Guide to the Fossil Invertebrates and Plants ” having 
run out of print, it is in part replaced by this book dealing 
with the Invertebrate Animals, whUe it is proposed that the 
Fossil Plants shall form the subject of a separate Guide. By 
describing the Galleries and their contents in a different 
order from that followed in the previous Guide, it is attempted 
to present the whole as a connected story. At the same 
time the book does not profess to be a complete systematic 
treatise, but relates only to the specimens actually exhibited 
in the Galleries. 
As in the other Guides to the fossil animals, the present 
one assumes on the part of the reader at least so much 
knowledge of the existing world of life as is conveyed by the 
corresponding Guides to the Department of Zoology. Since, 
however, many of the groups of animals herein dealt with 
are entirely or almost entirely extinct (e.g. Graptolites, 
Cystids, Trilobites, Ammonites), they have been treated more 
fully than those which are more familiar. 
The First Edition of this Guide, published in 1907, was 
written by Dr. Francis Arthur Bather, Assistant Keeper of 
Geology, who also has carefully revised the book for this, the 
Second Edition. Alterations, necessitated by the advance 
of science, by additions to the exhibited specimens, or by 
changes in the arrangement of the Galleries, have been made 
in every section. Figures 41, 49 and 65a have been replaced 
by new and better ones. 
In preparing the work, help was received from Mr. 
R. Bullen Newton and Mr. G. C. Crick in connection with 
the Mollusca ; from Mr. W. D. Lang in connection with the 
Bryozoa and Coelentera; and from Dr. W. T. Caiman in 
connection with the Arthropoda. Dr. Bather wishes^ to 
acknowledge the valuable aid of the same colleagues, and of 
Mr. T. H. Withers in checking the text for this edition. 
b 
