QUARTERLY JOURNAL 



MICROSCOPICAL SCIENCE. 



EDITED BY 



E. KAY LANKESTER, M.A., LL.D., F.R.S., 



(JNOKAltV FRI.I.OW OF EXKTER C0I.I.EGE,0XI'0UD; COURKSPONDENT Ol' TUK INSTITUTE 01' FRANCE 



AND OF TUB IMPKRIAI. ACADEMY OF SCIENCES OF ST. PETEBSBUUG, AND OK THE ACADEMY 



OF SCIENCES OK P M I LADE LP 11 1 A , AND OF THE ROYAL ACADEMY OF SCIENCES 



OF Turin; foreign member of the royal society of sciences of 



GOTTINGEN, AND OF THE RoYAL BOHEMIAN SOCIETY OF SCIENCES, AND 

 OF THE ACADEMY OF THE LINCEI OF ROME, AND OF TUK AMERICAN 

 ACADEMY OF ARTS AND SCIENCES OF BOSTON ; ASSOCIATE OF THE 

 ROYAL ACADEMY OF BELGIUM; HONORARY MEMBER OP THE 

 NEW YORK ACADEMY OP SCIENCES, AND OF THE 

 CAMBRIDGE PHILOSOPHICAL SOCIETY, AND OF 

 THE ROYAL PHYSICAL SOCIETY OK EDIN- 

 BURGH, AND OK THE 

 BIOLOGICAL SOCIETY OF PARIS. AND OF THE CALIFORNIA ACADEMY OF SCIENCES OF SAN FRANCISCO; 

 FOREIGN ASSOCIATE OF THE NATIONAL ACADEMY OF S C IE N CES. U. S., A N D MEMBER OF 

 THE AMERICAN PHILOSOPHICAL SOCIETY ; 

 DIRKCTOIl OF THE NATURAL HISTORY DEPARTMENTS OP THE BRITISH MUSEUM; LATE FIILLKUIAN 

 PROFESSOR OF PHYSIOLOGY IN THE ROYAL INSTITUTION OF GREAT BRITAIN; 

 LATK LIN'ACRE PROFESSOR OF COMPARATIVE ANATOMY AND FELLOW OF MERTON COLLEGE, OXFORD. 



WITH THE CO-OPERATION OF 



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



FELLOW AND TUTOR OF TRINITY COLLEGE, CAMBRIDGE; 



AND 



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



BEYER PROFESSOR OF ZOOLOGY IN THE OWENS COLLEGE, MANCHESTER. 



VOLUME 50.— New Series. 



1. 



LONDON: 



& A. CHURCHILL, 7, GREAT MARLBOROUGH STREET. 



1906. 



