PREFACE. 
The First Edition of this Guide was issued, without 
illustrations, on the 19th April, 1881 ; the second in 1882, 
illustrated with thirty -one- wood engravings ; a third, slightly 
altered, appeared in 1884. A fourth Edition, almost wholly 
re-written, with many fresh illustrations, appeared in 1886, 
and a fifth, with only a few alterations, in 1888. Of these 
five editions, altogether 15,000 copies have been issued. 
The publication of Mr. R. Lydekker’s Museum Catalogues 
of the “ Fossil Mammalia,” Parts I-Y. (1885-87), and the 
“ Reptilia and Amphibia,” Parts I-IY. (1888-90), has com- 
pelled the re-arrangement of a great part of these Collections, 
and also changed the plan of the Guide. Much additional 
information is given in this Edition, and the illustrations have 
been increased from forty-nine to two hundred and eleven. It 
has therefore been found necessary to subdivide it into two 
jiarts, each of which is larger than the former Guide. 
The writer is largely indebted to the authors of Nicholson’s 
and Lydekker’s “Palaeontology” (Yol. II., “ Yertebrata,” by 
R. Lydekker), from which numerous notes and extracts have 
been made in the compilation of this Guide, as well as to Mr. 
Lydekker, for much personal help. The Director, Professor 
Flower, has kindly read the sheets and made valuable sug- 
gestions and emendations. The Members of the Staff of the 
Department have also obligingly assisted in the work. 
Department of Geology, 
10th April, 1890. 
HENRY WOODWARD. 
