PREFACE. 



TN the following pages I have endeavoured to give an 

 A elementary account of Invertebrate Palaeontology, 

 adapted to the requirements of geological students. 

 With this object in view, I have devoted the greater part 

 of the space at my disposal to a consideration of those 

 groups of fossil animals which are most useful to the 

 stratigraphist, and have treated very briefly, those which 

 are of interest mainly to the zoologist. My plan has been 

 to give, in each group, first an account of its general 

 zoological features with a full description of the hard 

 parts, secondly the classification and characters of those 

 genera which are important geologically, and thirdly a 

 sketch of the present and past distribution of the group. 



Since Palaeontology can be learnt only by students 

 who have access to a collection of fossils, I have purposely 

 refrained from using figures to illustrate genera, and have 

 confined myself to those required to explain structure and 

 terminology. 



