viii INVERTEBRATE PALAEONTOLOGY 



failed. To beginners who find the book too abstruse 

 or too dull I apologize herewith, and hope that some 

 grain of interest or instruction may have survived their 

 flails. 



The illustrations, both photographs and drawings, 

 have been made by myself. All of the former, and 

 a large majority of the latter, are wholly new they 

 represent specimens in the collections of this Depart- 

 ment. In the few cases where figures have been 

 adapted from drawings previously published, acknow- 

 ledgment is made; and, since such "copies" usually 

 show some modification (apart from unintentional 

 clumsiness of draftsmanship) from their originals, 

 responsibility for their accuracy must fall on me. 



To Mr. D. M. S. Watson I desire to express my 

 extreme indebtedness for helpful criticism of the manu- 

 script, and to Drs. F. A. Bather and H. Woodward my 

 appreciation of their kindly interest and encouragement 

 in this work, as in all that I have done. To these 

 friends much of what is good in the book must be 

 ascribed, whether directly or indirectly; for its many 

 shortcomings they can in no way be held responsible. 



H. L. H. 



UNIVERSITY COLLEGE, READING, 

 January 1920 



