PREFACE 



As this Volume is conducted on precisely the same principles as those which 

 characterized the two previous instalments of the work, no introductory preface is 

 needful. I cannot, however, dismiss the Volume without returning my sincere thanks 

 to the many friends who have aided me by their valuable assistance. 



More especially are my acknowledgments due to those eminent naturalists, such 

 as Mr. Blackwall and Mr. Busk, who liberally permitted the use of figures taken 

 from unpublished volumes ; and to the officers connected with the Zoological Depart- 

 ment of the British Museum, without whose constant assistance I could not have 

 carried out so laborious a task. 



