QUARTERLY JOURNAL 
MICROSCOPICAL SCIENCE. 
HONORARY EDITOR: 
Sm BAY DANKESTER,.K.C-B:, M.A., D.Sc, LL.D., PRS. 
EDITOR: \ 
EDWIN S. GOODRICH, M.A., F.R.S., 
PROFESSOR OF COMPARATIVE EMBRYOLOGY IN THE UNIVERSITY OF OXFORD}; 
WITH THE CO-OPERATION OF 
SYDNEY J. HICKSON, M.A., F.R.S., 
BEYER PROFESSOR OF ZOOLOGY IN THE UNIVERSITY OF MANCHESTER ; 
GILBERT C. BOURNH, M.A., D.Sc., F.R.S., 
LINACRE PROFESSOR OF COMPARATIVE ANATOMY IN THE UNIVERSITY OF OXFORD; 
J. GRAHAM KERR, M.A., F.R.S., 
REGIUS PROFESSOR OF ZOOLOGY IN THE UNIVERSITY OF GLASGOW ; 
E. W. MACBRIDE, M.A., D.Sc., LL.D., F.R.S., 
PROFESSOR OF ZOOLOGY AT THE IMPERIAL COLLEGE OF SCIENCE AND TECHNOLOGY ; 
GP. BIDDER, M-A.,Se.D. 
VOLUME 65. New Series. 
WITH LITHOGRAPHIC PLATES AND TEXT-FIGURES 
OXFORD UNIVERSITY PRESS, 
HUMPHREY MILFORD, AMEN CORNER, LONDON, E.C. 4. 
1921 
