VII PREFACE. 
British Museum, the author is indebted for kindly assistance towards the correct 
identification of many of the specimens figured. For substantial services in the revision 
of the proof sheets acknowledgments are especially due to Mr. Robert Bell, M.A. 
The author has, finally, to acknowledge his obligations to Messrs. Waterlow 
and Sons Limited and their staff of expert departmental managers for the pains- 
taking and, to himself, eminently satisfactory manner in which they have carried out 
his views concerning the production of this volume. 
Lonpon, 
February 1st, 1897. 
