INTRODUCTORY AND EXPLANATORY . xix 
The connection between the two is explained on 
page 76. However, the reader may rest as- 
sured that these restorations are infinitely more 
nearly correct than many figures of living 
animals that have appeared within the last 
twenty-five years, and are even now doing 
duty. 
The endeavor has been made to indicate, at the 
end of each chapter, the museums in which the 
best examples of the animals described may be 
seen, and also some book or article in which fur- 
ther information may be obtained. As this book 
is intended for the general reader, references to 
purely technical articles have, so far as possible, 
been avoided, and none in foreign languages 
mentioned. 
For important works of reference on the 
subject of paleontology, the reader may consult 
“4 Manual of Paleontology,” by Alleyne Nich- 
olson and R. Lydekker, a work in two volumes 
dealing with invertebrates, vertebrates, and 
plants, or “.4 Text-Book of Paleontology,” by 
Karl von Zittel, English edition, only the first 
volume of which has so far been published. An 
admirable book on the vertebrates is “Outlines 
