370 Messrs. A. E. Boycott and J. W. Jackson on 



1914; and (2) the River Wye between Whitclmrcli and 

 ]\lonmouth, where it forms the boundary between Hereford- 

 shire and Gloucestershire, collected in July 1913. The two 

 localities are essentially different in character, the canal 

 being yerj sluggish, while in the Wye the species is only to 



be found in shallow quick-running rapids. Of the Barton 

 series the whole were dissected and examined, in all 288, 

 though naturally in collecting the specimens more attention 

 was paid to large individuals. The same selection was made 

 in the case of those from the Wye, but of these only 93 of 



