c/J^Mt^-'c ) 



New Series, No. 223 (Vol. 56, Part 3). Price 10s. net. 



Subscription per volume (of 4 parts) 40s. net. 

 APEIL, 1911. 



THE 



QUARTERLY JOURNAL 



OF 



MICROSCOPICAL SCIENCE. 



EDITED BY 



Sir ray LANKESTER, K.C.B., M.A., D.Sc, LL.D., F.R.S., 



HOKORAUT PKI.I.OW OF EXETER COM.KGE, OXFORD ; 

 MEMBER OP THE INSTITUTE OK KRANCK (asSOCI£ £tRAXGEB DE L'aCADEMIE DES SCIENCES) ; 

 COBBKSPONDBNT OF THE IMPERIAL ACADEMY OF 8CIK>CE8 OP 8T. PETER8BUUG, AKD OK THE 

 ACADKMY OP SCIENCES OP F UI L A DE I,r II I A, AND OF THE ROYAL ACADEMY OF SCIKNCES 

 OK TURIN; FOREIGN MEMBKR OF TUK ROYAL SOCIETY OF SCIENCES OP 

 GOTTIN6EN, AND OF THK UoYAI. BOHEMIAN SOCIETY OF SCIENCES. AND 

 OP THE ACADEMY OP THE I.INCRI OF ROME, AND OF THE AMERICAN 

 ACADEMY OF ARTS AND SCIENCES OP BOSTON ; ASSOCIATK OF THE 

 ROYAL ACADEMY OF BELGIUM; HON<JRARY ME 51 ERR oF THE 

 NEW YORK ACADEMY OF SCIKNCES, AND OF THK 

 CAMBRIDGE PHILOSOPHICAL SOCIETY, AND OP 

 THK ROYAL PHYSICAL SOCIETY OF EDIN- 

 BURGH. AND OF THE 

 BIOLOGICAL SOCIRTT OF PARIS, AND OP THK CALIFORNIA ACADEMY OF SCIENCES OP SAN FRANCISCO, AND 

 OP THE ROYAL ZOOLOGICAL AND MALAC OLO GIC A L SOCIETY OF BELGIUM; 

 CORRESPONDING MEMBER OF THE 8ENKENEERG ACADEMY OF FR AN KFURT-A-M ; 

 FOREIGN ASSOCIATE OP THE NATIONAL ACADEMY OF SCIKNCES, U.S.. AND MEMBER OP THE 

 AMERICAN PHILOSOPHICAL SOCIETY ; 

 HONORARY FELLOW OF THE ROYAL SOCIETY OF EDINBURGH; 

 LATE OIRKCTOR OP THE NATURAL HISTORY DEPARTMENTS OF THK BRITISH MUSKUM; LATE PRESIDENT OF THE 

 BRITISH ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE; IjATE FULI.KRIAN PROFESSOR OP 

 PHYSIOLOGY IN THE ROYAL INSTITUTION OP GREAT BRITAIN. 

 LATE MNACRE PROFESSOR OF COMPARATIVE ANATOMY AND FELLOW OF MERTON COLLE GE , OXFU R D ; 

 EMERITUS PROFESSOB OF ZOOLOGY AND COMPARATIVE ANATOMY IN UNIVERSITY COLLEGE, UNIVERSITY OP LONDON. 



WITH THE CO-OPERATION OF 



ADAM SEDGWICK, M.A., F.R.S., 



FELLOW OF TRINITY COLLEGE, CAMBRIDGE. AND PROFESSOR OF ZOOLOGY IN THE IMPERIAL COLLEGE OP 

 SCIENCE AND TECHNOLOGY, LONDON; 



SYDNEY .J. HICKSON, M.A., F.R.S., 



iSSOR OF ZOOLOGY IN THE UNIVERSITY OF M, 



E. A. MINCHIN, M.A., 



BKYKR PROFESSOR OF ZOOLOGY IN THE UNIVERSITY OF MANCUESTKRi 



PROFESSOR OF PROTOZOOLOGY IN THE UNIVERSITY OP LONDON; 

 AND 



GILBERT C. BOURNE, M.A., D.Sc, F.R.S., 



LINACBE PROFESSOR OF COMPARATIVE ANATOMY, AND PKLLOW OF MERTON COLLEGE. OXFORD. 



WITH LITHOGRAPHIC PLATES AND TEXT-FIGURES. 



LONDON. 

 J. & A. CHCJRCHILL, 7 GREAT MARLBOROUGH STREET. 



1911. 



Adlard and Son, Impr.,] 



[London and Dorking 



