nini ^ '• 



MS^^ 



New Series, No. 188 (Vol. 47, Part 4). Price 10s. 



MAECH, 1904. 



QUATITERLY JOUllNAL 



OK 



MICROSCOPICAL SCIENCE. 



F.IHIKI) IIY 



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



FRl.l.OW <»K KXKTKK CoM.l 

 OP TUB LMPKItlAI. ACADKMY OK SC 

 ' SCIKNCKS OF PIIII.AnEI.pniA ; 

 SCIENCES OF GOTTINGEN AND O 

 AND OF THK ACADEMY OF TllK 

 ACADEMY OF ARTS AND SC 



O.XFORD ; CORUKSPONDKNT I 

 (CIKNCES OP ST. PKTICKSBUII 

 > R K I G N M F, M B K R OF T II 1 

 THE RUYAI. BOHEMIAN SO) 

 MNCEI OF ROME, AND O 

 SNCES OF BOSTON : 



ROYA 



4 S T r T i; T E 

 • TllK AC A 

 SOCIETY 



CIKTY "F SCIENCES, 



F TIIR AMKIIICAN 



CIATE OK THE 



R nF THE 



f THE 



noYAI. ACADEMY OF BEI-GIUM; HONORARY ME 

 NEW YORK ACADEMY OF SCIENCES, AN] 



CAMBRIDGE PHILOSOPHICAL SOCIETY, AND OF 

 THE UOYAI. PHYSICAL S(tCIETY OF EDIN- 

 BUflGU ; HONORARY MEMBER OF THE 

 BIOLOGICAL SOCIETY OK PARl»; 

 FOREIGN ASSOCIATE OF THE NATIONAL ACADEMY OF SCIENCES, U 

 THE AMERICAN PHILOSOPHICAL SOCIETY \ 

 DIRKtTItK OK THE NATURAL HISTORY DEPARTMENTS OF THE BRITISH MUSEUM; LAT 

 PUi>KKS!»rtR OF PHYSIOLOGY IN THK llOYAL INSTITUTION OF GREAT nRITAI:> 

 LATE LINACRE PROFESSOR OF COMPARATIVE ANATOMY AND FELLO 



AND MEMBER OF 



MERTON COLLEGE, OXFORD. 



WITH THE CO-OPERATION OF 



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



FELLOW AND TUTOR OK TRINITY COLLEGE, CAMBRIDGE; 



W. F. R. WELDON, M.A., F.R.S., 



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



BEYER FnOFUSSOR OP ZOOI.UGY IN THK OWENS COI.I.KGK, M ANCllESTK R. 



WITH LITHOGRAPHIC PLATES AND ENGRAVINGS ON WOOD. 



LONDON: 

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



1904. 



Adlard ami Son,] 



[London and Dorkinc 



