PREFACE. Yll. 



I hardly know how sufficiently to express my thanks to 

 Herr Temminck and Herr Schlegell, of Leyden ; to Professor 

 Lichtenstein and Herr Deppe, of Berlin ; to Drs. Cretzschmarr 

 and Riippell, and Senator Von Heyden, of Francfort, for the 

 courtesy and attention which they shewed me during my 

 visits to the various museums under their direction ; indeed 

 with such liberality that it would be impossible, however 

 desirable, to imitate them in our more populous town. 

 In each of these museums all the specimens w-ere 

 intrusted to me, to describe, draw, or examine them, as 

 might best suit my purpose, without any restraint, except 

 that, at Leyden, Herr Temminck requested I would indicate 

 in what Museum I had seen it, and the name under which 

 it was there described, a rule which I hope I have most faith- 

 fully kept. At Francfort some specimens w^ere even sent 

 to my hotel, that they might be examined more at my leisure. 

 I cannot here omit to mention the names of Sir James 

 Mac Grigor, and Dr. Burnet for their kindness in allowing 

 me to examine the Museum of Fort Pitt Chatham and of 

 Haslar Hospital, and to Dr. Horsfield for the faciUties which 

 he gave me of seeing the Reptiles in the IMuseum of the 

 India House, and more especially of comparing and copying 

 the drawings made under the superintendence of Dr. Hamil- 

 ton in India. 



Besides those w^ho have assisted me with specimens, I 

 cannot forget the kindnesses shewn me by Prince Massena 

 Baron Ferussac, and M. Deshayes, at Paris ; Professor 

 Reinwardt, at Leyden ; Professors Kunth and Ehrenberg, at 

 Berhn ; and Herrn Oken, Fischer, Otto, Boie, and numerous 

 other German, Swedish, and Danish naturalists at Hamburgh, 

 in whose society I spent one of the happiest weeks of my life. 

 The opportunity of examining the museums of the north 

 of Europe not occurring till the body of the monograph was 

 printed, I have been reduced to the necessity of adding the 



