A TREATISE 



ON THE 



BRITISH FRESHWATER 



BY 

 G. S. WEST, M.A., A.R.C.S., F.L.S., 



PROFESSOR OF NATURAL HISTORY AT THE ROYAL AGRICULTURAL COLLEGE, 



CIRENCESTER ; FORMERLY SCHOLAR AND HUTCH1NSON RESEARCH 



STUDENT OF ST JOHN'S COLLEGE, CAMBRIDGE. 



CAMBRIDGE 



AT THE UNIVERSITY PRESS 

 1904 



