PREFACE. 



To accelerate the progress of this work, it has been found advisable 

 to publish the present volume in advance of the thirteenth. The 

 manuscript of the latter is in course of preparation, but is not 

 expected to be completed before 1889. However, as its limits are 

 well-defined, comprising the remainder of the Acromyodian 

 Passeres, no confusion can arise from this break in the series of 

 volumes, and any inconvenience which may be caused by it will be 

 of a merely temporary nature. 



ALBERT GUNTHEll, 



Keeper of the Department of Zoology. 



British Museum (N. H.), 

 May 17, 1888. 



