New Series, No. 200 (Vol. 50, Part 4). Price lOs. net 



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



NOVEMBER, 1906. 



THE 



QUARTERLY JOURNAL 



OF 



MICROSCOPICAL SCIENCE. 



EDITED HY 



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



n(J^OIlAKY FELLOW OF EXETKR C O M.KG R , OX FO II U *, C O R U KS P 0> D K N T OF TUE INSTITUTE OF FRANCE 

 A>D {IF THB IMFKRIAI, ACADEMY OF SCIENCES OF ST. PETERSBURG, AND OF THE ACADEMY 

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

 OF TURIN; FOREIGN .MEMBER OF TUK ROV.AL SOCIETY OF SCIENCES OP 

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

 OP THE ACADEMY OP THE LINCEI OF ROME, AND OF THK AMERICAN 

 ACADEMY OF ARTS AND SCIENCES OF BOSTON; ASSOCIATE OK THE 

 ROYAL ACADEMY OP BELGlirM: HONfJRAKY MEMBER '>F THE 

 NEW YORK ACADEMY OF SCIENCES, AND OF THE 

 CAMBRIDGE PHILOSOPHICAL SOCIETY, AND OF 

 THE ROYAL PHYSICAL SOCIETY OF EDIN- 

 BURGH, AND OF TUE 

 BIOLOGICAL SOCIETY OF PARIS, AND OF T il K CALIFORNIA ACADEMY OF SCIENCES OF SAN FRANCISCO; 

 FOREIGN ASSOCIATE OF THK NATIONAL ACADEMY OF S CI E NCE3, U.S ., AN D MEMBER OF 

 THE AMERICAN PHILOSOPH ICAL SOCIETY ; 

 DIRECTOR OF TUB NATURAL HISTORY DEPARTMENTS OF THE BRITISH MUSKUM; LATE PULLKRIAN 

 PROFESSOR OF PHYSIOLOGY IN THK ROYAL I N STITUTIO N O F G R E AT B R IT AI N ; 

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



WITH THE CO-OPERATION OF 



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



PKLLOW AND TUTOR OF TRINITY COLLEGE, CAMBRIDGE; 



ANB 



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



BEYER, PROFi;SSOR OF ZOOLOGY IN TUE OWENS COLLEGE, M A N C H E ST K R . 



WITH LITHOGRAPHIC PLATES AND TEXT-FIGURES. 



LONDON: 



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



1906. 



Adlard and Son, Impr.,] 



[London and Dorkin?. 



