PREFACE. 



to each other, and especially the friendship and hostility 

 of different species ; and these are for the most part re- 

 ferred to the nature of their food, and their mode of pro- 

 curing it. The notices of fish are not so numerous as those 

 of other groups : this would necessarily arise from the diffi- 

 culty of observation. At the conclusion of the book, an 

 essay on bees and their congeners is given at considerable 

 length. 



BOOK X. This book, in all probability erroneously as- 

 cribed to Aristotle, is occupied with a treatise on the 

 causes of barrenness in the human species. It appears 

 to be rather a continuation of the seventh book, which ends 

 abruptly ; but it is well placed at the end, as no genuine 

 work of our author. 



