PEEFACE. vu 
The collection of Mammalia likewise, so far as it went, was a great success ; but 
this section being more difficult to deal with, and requiring more skill and labour as 
well as time for the capture and preservation of its members, a great deal in it yet 
remains to be achieved. 
The recent events in the Egyptian Sudan now throw open a vast field for 
zoological research, and I trust that those who have assisted me in the past may 
see their way to continue their assistance in the future, and so enable me to make 
the volume on the Mammalia, now in progress, as complete as possible. 
It would have been almost impossible for me to have undertaken this work had 
I not had the co-operation of the Natural History Department of the British Museum 
heartily accorded to me by Sir William Flower. 
To Mr. G. A. Eoulenger, Custodian of the unrivalled Herpetological collections 
of that Institution, I feel under a debt of gratitude which it is difficult to express, 
as his assistance met me in so many ways. Not only was his vast experience 
freely proffered ; but the facilities he gave to me, in the way of free access to 
the specimens under his charge, proved invaluable. But my indebtedness does 
not stop here, because I have made free use of his published Catalogues ; and 
as one out of many illustrations may be mentioned the fact that the dentition of 
the various genera of Snakes given in this volume rests entirely on Mr. Boulenger's 
Catalogue of that Group. Moreover, I have followed his classification of the Reptilia 
and Batrachia. 
I am indebted to Professor G. B. Howes for his having kindly permitted one 
of his assistants, Mr. Vanstone, to make for me a few preparations of the epidermal 
covering of the digits of some lizards. 
The Plates, illustrating the species described in this volume, have nearly all been 
drawn by Mr. P. J. Smit, some of them from life. My impression is, that Mr. Smit 
has very skilfully and successfully delineated the different species, and, in this view, I 
think that I shall have the support of other herpetologists. Moreover, he was deputed 
by me to visit the Royal Museum of Natural History, in Stockholm, in order to 
b 
