PREFACE. 
Ix the present edition a special effort has been made to 
replace technical terms (other than scientific names), so far as 
possible, by words in ordinary use. This, it is hoped, will 
render the " Guide " more acceptable to the general reader, 
while in no wise detracting from its usefulness to the more 
scientific student. Like its predecessor, this edition has been 
revised and brought up to date by Mr. E. Lydekker. 
E. EAY LANKESTER. 
British Museum (Natural History). 
Sejytember, 1906. 
