-•^ > ^, 



New Series. No. 221 (Vol. 56, Part 1). Price 10s. net. 



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

 DECEMBEE, 1910. 



THE 



QUARTERLY JOURNAL 



OF 



MICEOSCOPICAL SCIENCE. 



EDITED MV 



SiE RAY LANKESTER, K.C.B., M.A., D.Sc, LL.D., F.R.S., 



MBHBEr. OK THE IMSTITUTK OF fKANCK (aSSOCI^ f;TRA>GER DE L'aCADEMIB DE3 SCIENCES) ; 



COHKKSPONDKNT OP THK IMPKKIAI. ACAltKMy OF SCIKNCKS OF 8T. FKTKKSBUHG, A>D OF TUE 



ACADKMY np aCIBNCF.a OF P II I L A t> K I. P II I A . AND OF THE ROYAI. ACADEMY OF SCIENCES 



OF Turin; fokkign membkil of the royai. society of sciences of 



SOTTINGEN, AND OF THE H O Y A I- BOHEMIAN 30CIKTY OF SCIENCES, A N l> 



OF THE ACADEMY OF THE l.INCEI OF HOME, A W D OF THH AMERICAN 



ACADEMY OF ARTS AND SCIENCES OF BOSTON ; ASSOCIATE OF THK 



ROYAI. ACADEMY OF BELGIUM; HONURAKY MEMBKR '»K THE 



NEW YORK ACADKMY OK SCIENCES, AND OF THE 



CAMBRIDGE P li 1 1.oS O I- H IC AI. SOCIEir, AND OF 



THE ROYAI, PIIYSICAI. SOCIETY OK EDI?<- 



BURGH, AND OK THE 



BIoLUeiCAL aoClKTY OF PAIlISt AND OF THE CAI.IFOKNIA ACADEMY OF SCIENCES OF SAN FftANCISCQ, AND 



OF THK ROYAL ZOOLOGICAL AND M A L ACOI.O GIC A I- SOCIETY OK BELGIUM; 



CORRESPONDING MEMBER OF THE SENKENDERG ACADEMY OF F B AN KFU RT'A'M ; 



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



AMERICAN PHILOSOPHICAI. SOCIETY ; 



HONORARY FELLOW OF THE ROYAI. SOCIETY OK EDINBURGH; 



LATE DIKKCTOK OK THE NATURAL HISTORY DEPARTMENTS OK THE BRITISH MUSEUM; LATE P R KS I DE NT O F T H E 



BklTISU ASSOCIATION FOR THE ADVANCEMENT OP SCIENCE; LATE FUM.KItlAFl PK0FKS90K OK 



PHYSIOLOGY IN THK ROYAL INSTITUTION OK GREAT BRITAIN . 



LATE MNACRE PROPE9ROR OF COMPARATIVE ANATOMY AND FELLOW liF MERTON COLLR GK , OX F O R D ; 



EMERITUS PROFESSOR OF ZOOLOGY AND COMPARATIVE ANATOMY IN UNIVERSITY COLLEGE. UNIVERSITY OF LONDON. 



WITH THE CO-OPKUATION OF 



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



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

 SCIENCE AND TECHNOLOGY, LONDON"; 



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



^aSOR OF ZOOLOGY IN THE UNIVERSITY OF .M 



E. A. MINCHIN, M.A., 



lYRR PROFESSOR OF ZOOLOGY IN THE UNIVERSITY OF .MANCHESTKB; 



PROFESSOR OF PRO I OZ OOLOGY IN THE UNIVERSITY OK LONDON; 



AND 



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



MNACRE PROFESSOR OF COMPARATIVE ANATOMY, AND FKLLOW OF MERTON COLLEGE, OXFORD, 



WITH LITHOGRAPHIC PLATES AND TEXT-FIGURES 



LONDON. 

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



1910. 



Adlard and Son, Impr.,] 



[London and Dorking. 



