viii PBEFACE. 
examine and figure some Linnean types of snakes preserved in that Institution. In 
addition to doing so, he made notes on the specimens for my information, and for what 
he accomplished on that occasion and for his work generally, 1 beg to assure him of 
my high appreciation. 
The remaining Plates, 10 in number, are the work of Mr. J. Green and 
Mr. H. Gronvold. 
The map accompanying this volume was specially compiled by Mr. Reeves, of the 
Royal Geographical Society, to indicate the positions of the chief localities mentioned 
in the text, and was so effectively transferred to stone by Mr. J. Green, that the 
prints thrown off by Messrs. Mintern Brothers display remarkable clearness. 
To Professor Dr. Oscar Boettger, of Frankfort-on-the-Main ; to Count M. G. Peracca, 
of Turin; to Professor F. A. Smitt, of Stockholm; to Dr. Gustav Tornier, of Berlin; 
to Professor Leon Vailiant and M. F. Mocquard, of Paris ; and to Dr. Franz Werner, 
of Vienna, I beg to convey my thanks for their courtesy on the various occasions on 
which I had to apply to them for assistance. 
The Introduction is illustrated by a series of photographs, which have been very 
generously placed at my disposal for the purpose by Mrs. Theodore Bent, Mr. A. J. 
Cholmley, and Professor Flinders Petrie, to all of whom I proffer my best thanks. 
Those of the Erba and Elba groups of mountains have a special interest, as the 
regions which they illustrate are but little known. For the four phocographs of 
the Libyan desert, I am indebted to the very valuable Album issued by Remele, one 
of the members of the Expedition under the late Dr. Gerhard Rohlfs. All of these 
photographs have been very successfully reproduced by the Swan Electric Engraving 
Company. 
71 Harrington Gardens, London, 
1st November, 1898. 
