^1 



New Series, No. 199 (Vol. 50, Part 3). Price lOs. net, 



AUGUST, 1906. 

 THE 



QUARTERLY JOURNAL 



OF 



MICROSCOPICAL SCIENCE. 



EDITKI) HY 



E. RAY LANKESTER, M.A., D.Sc, LL.D., F.R.S., 



HONORARY FELLOW OF EXETER COLLEGE. OXFORD ; CORRESPONDENT OK TUH INSTITUTE OF FRANCE 

 AND OF TUB IMPERIAL ACADEMY OF SCIENCES OP ST. PBTRRSBURG, AND OF THE ACADEMY 

 OF SCIENCES OF PHILADELPHIA, AND OF THE ROYAL ACADEMY OF SCIENCES 

 OF TURIN; FOREIGN MEMBRH 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 THR AMERICAN 

 ACADEMY OF ARTS AND SCIENCES OF BOSTON I ASSOCIATE OF THE 

 ROYAL ACADEMY OF BELGIUM; HONORARY MEMBER nF THE 

 NEW YORK ACADEMY OF SCIENCES, AND OF THR 

 CAMBRIDGE PHILOSOPHICAL SOCIETY, AND OF 

 THE ROYAL PHYSICAL SOCIETY OF EDIN- 

 BURGH* AND OF TUB 

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

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

 THE AMERICAN PHILOSOPHICAL SOCIETY ; 

 DIRECTOR OF THE NATURAL UISTOUY DEPARTMENTS OK THE BRITISH MUSEUM; LATE FULLKRIAN 

 PROFESSOR OF PHYSIOLOGY IN THE ROYAL INSTITUTION OF GREAT BRITAIN; 

 LATE LINACRE PROFESSOR OF COMPARATIVE ANATOMY AND FELLOW i»F MERTON COLLEGE, OXFORD. 



WITH TJIE 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., 



BEIER PBOriiSSOR OF ZOOLOGY IN THE OWENS COLLEGE, MAXCUESTKR. 



WITH LITHOGRAPHIC PLATES AND TEXT-FIGURES. 



LONDON : 

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



1906. 



Adlardand Son, Impr.,] 



[London and Dorking. 



