X1¥ AUTHOR'S PREPACE. 
To the publishers his thanks are due for their liberality 
in the matter of illustrations, and the readiness with which 
they have responded to suggestions. 
With regard to minor illustrations the following acknow- 
ledgments are due :— 
To the Paleontological Society of Great Britain for 
permission to reproduce three of the illustrations in Sir 
Richard Owen’s great work, British Fossil Reptiles, pub- 
lished in their yearly volumes, viz. Figs. 3, 4, and 8. 
To Messrs. Bell and Co. for the following cuts from the 
late Dr. Gideon A. Mantell’s works: viz. Figs. 12, 14 
20, 33, 37, 38. 
To Messrs. A. and C. Black for the following cuts from 
Owen’s Paleontology: viz. Figs. 51, 54, 56, 57. 
’ 
Appendix IV. contains a list of some of the works of 
which the writer has made use; but it would be impossible 
within reasonable limits to enumerate all the separate 
papers which have necessarily been consulted. The reader 
will find numerous references, such as “ Case Y on Plan,” 
in brackets; these refer to the plan given at the end of 
the excellent little Guide to the Exhibition Galleries in the 
Department of Geology and Palaeontology in the Natural 
Ffistory Museum, Cromwell Road (price one shilling), which 
visitors to the Museum are advised to obtain. 
