VOL. x] HIRDS NEW TO IJKITISH LIST. 257 



Eastern Great Reed- Warbler [Acrocephahis a. orienialis). 



The tone of colour varies individually in this form as it does 

 in the typical Euro]>ean bird, and neither in winter nor in 

 summer ])lnmage can the two forms be distinguished by their 

 coloration. 



The Eastern form, however, is smaller, as will be seen by 

 the measurements given below. The 4th primary is usually 

 longer than the 2nd. but occasionally equal, though never 



A ORI ENTALIS 



shorter, while in the typical form the 4th is always shorter 

 than the 2nd. There are also small differences in the relative 

 lengths of the other primaries, as will be seen by the details 

 given below. 



The following are measurements in millimetres of twelve 

 males and females of each form : 



wing tail tarsus bill from skull 



A. a. arundinaceus ^ 90-103 68-81 27-31 21-24 



A. a. orie.ntalis ^ 80-92 06-77 27-30 21-24 



A. a. arundinacevs $ 88-94 

 A. a. orientalis $ 77-84 



