INTRODUCTION. 



In the first volume will be found an account of the Letnuroidea, 

 and the Anthropoidea as far as the group of the Macaques of 

 the family Cercopithecidce. The second volume continues with 

 the latter genus, and contains the rest of the Monkeys, and 

 the Apes, as well as a summary of the geographical distribution 

 of the species of the Order Primates. 



I have not attempted to write a complete synonymy of the 

 species of Monkeys. The literature is scattered over many, 

 often obscure, periodicals, and without seeing the actual speci- 

 mens described by some of the older writers, it would be easy 

 to introduce a great deal of confusion into the synonymy. I 

 have, therefore, only attempted to give the principal references. 



I must express my obligation to Dr. Giinther, F.R.S., the 

 Keeper of the Zoological Department in the British Museum, 

 for the facilities of study afforded to me in that institution. 

 To Mr. Old field Thomas I am likewise greatly indebted for 

 much assistance, and for many a kindly hint. 



Dr. Forsyth Major, who is well-known as one of the fore- 

 most authorities on the Lemurs, not only gave me valuable 

 information as to the species and literature of the Lemiiroidea^ 

 but was even so good as to furnish me with the descriptions 

 of several new species. 



