/ 



/^^ybf<^^iX- 



^ 



QUARTERLY JOURNAL 



OK 



MICROSCOPICAL SCIENCE. 



Sir 



EDITED BY 



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



MEMBE.' OK THE INST.TUTK OK KKANCE (aSSOCI^ £tRANGER DE ■■ *C-'>""= '' f' ""^^^ ^^'^^'^.^g' ' 



COB KSPONUKr.T OK THE I M P K R I A I, ACADEMY OK SCIENCES OK ST. P EIK K 8 B U U G A N D OK T „ g 



ACADK"r,.K SCIENCES OK P HI I,A I.E I.P MI A , AND OK THE ROYA,. A""","" "^^^\^'^^<=^' 



OK TURIN; KORKIGN MEMBKR OK TME ROYAI, SOCIETY '>U"IT L^ 



GOTTINGEN, AND OK THE U O V A I. BOHEMIAN SOCIETY "•" ,f "".^"j.V- *J^ 



OK THE ACADEMY OK THE I.INCEI OK ROME, AND OF THK AMERICAN 



ACADEMY OF ARTS AND SCIENCES OF BOSTON : ASSOCIATE OK THK 



BOYAI, ACADEMY OK BELGIUM; HONORARY MEMEHR oK THK 



NEW YORK ACADEMY OK SCIENCES, AND OF THK 



CAMBRIDGE PHILOSOPHICAL SOCIETY, AND OP 



THE ROYAL PHYSICAL SOCIETY OF EDIN" 



KIOLOGIC*.. SOCIETY OK PARIS, AND "^ T.^rcVLIK^MrN?! ACADEMY OK SCIENCES^^^^^ 



DP THK ROYAL ZOOLOGICAL AND MALACOLOGICAL SOCIETY OK BELGIUM, 

 CORRESPONDING MEMBER OF THE SENKENBEBG ACADEMY OF ^^'■^l^^^l^^^' -„^ 

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

 AMERICAN PHILOSOPHICAL SOCIETY; 

 HONORARY FELLOW OF THE ROYAL SOCIETY OK EDINBURGH; po„,,npNT OF THE 



LATE U.BKCTOR OK THK NATURAL HISTORY DEPARTMENTS OK THE BRITISH « ^,7"' " " ''*" /gY.'J.roK 

 BRITISH ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE; LATE KULLKRIAN PROKK880R OK 



PHYSIOLOGY IN THK ROYAL I N STITUTION OK GR EAT BRITAIN . oXKORd; 



I.ATKLINACRE PROFESSOR OF COMPARATIVE ANATOMY AND ■''^""'^ ''^ ''7/°'; '^""•^^^^^""o^^^ 

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



WITH THK rO-OPEKATlON OP 



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



FFLLOW OK TRINITY COLLEGE, CAMBRIDGE. AND PROFESSOR OF ZOOLOGY IN THE IMPERIAL COLLEGE OK 



SCIENCE ANn TECHNOLOGY, LONDON; 



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



BEYER PROFESSOR OK ZOOLOGY IN THE UNIVERSITY OF MANCHESTER, 



E. A. MINCHIN, M.A., 



PROFESSOR OK PROTOZOOLOGY IN THE UNIVERSITY OK LONDON; 



AND 



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



LINACRE PROFESSOR OF COMPARATIVE ANATOMY, AND FKLLOW OF MEBTON COLLEGl., OXFORD. 



VOLUME 55.— New Series. 

 mxi\ ^"itl^ograpbic f latcs anb 3Le*-t-ifigu«s 



LONDON: 

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



1910. 



