EWE: 
CAMBRIDGE NATURAL HISTORY 
EDITED BY 
S. F. HARMER, Sc.D., F.R.S., Fellow of King’s College, Cambridge ; 
Superintendent of the University Museum of Zoology 
AND 
A. E. SHIPLEY, M&A., Fellow of Christ’s College, Cambridge ; 
University Lecturer on the Morphology of Invertebrates 
VOLUME X 
PE 
