X I'KEFxVCE. 



kingdoms of nature, already affording ample occupa- 

 tion for a single labourer. 



The catalogue of authors whose works have fur- 

 nished me with the principal facts detailed in these 

 volumes, is too long for insertion in this place. I 

 have not encumbered the pages of the Vv^ork by con- 

 tinual citations of authorities ; but have given refer- 

 ences to them only when they appeared to be parti- 

 cularly requisite, either as bearing testimony to facts 

 not generally known;, or as pointing out sources of 

 more copious information. It may, how^ever, be pro- 

 per to mention, that I have more especially availed 

 myself of the ample materials on Comparative Anato- 

 my and Physiology contained in the works of Cuvier, 

 Blumenbach, Cams, Home, Meckel, De Blainville, 

 Latreille, and St. Hilaire, and in the volumes of the 

 Philosophical Transactions, of the Memoires and An- 

 nales du Museum, and of the Annales des Sciences 

 Naturelles. I should be ungrateful were I not also 

 to acknowledge the instruction I have derived from 

 my attendance on the lectures at the Royal College of 

 Surgeons, delivered successively, during many years, 

 by the late Sir Everard Home, Sir Astley Cooper, 

 Mr. Lawrence, Mr. Brodie, Mr. Green, and Sir 

 Charles Bell; and also from those of Professor Grant, 



I 



at the University of London. 



I have likewise to return my thanks for the liberal 

 manner in which the Board of Curators of the Hunte- 



