New Series, No. 227 (Vol. 57, Part 3). Price 10s. net. 
Subscription per volume (of 4 parts) 40s. net. 
FEBRUARY, 1912. 
THE 
QUARTERLY JOURNAL 
OF 
MICROSCOPICAL SCIENCE. 
KIMTKI) HY 
Sir RAY LANKESTER, K.C.B., M.A., D.Sc., LL.D., F.R.S., 
HONORARY K K 1.1.0 W O K EXETER COl.I.KGK, OXKdltll ; 
MEMBER OK T II K INSTITUTE OK FRANCE (.ASSOClfi &TRANGER DE I.’a.CADEMIF, DES SCIENCES) J 
COKKKSPONUKNTOK THE 1MPKKIAI, ACAIlttMY OK SCIENCES OF ST. PETKUSBUKG, A N li OK THE 
ACADEMY OK SCIENCES OK P II 1 1. A II EI.K II I A , AND OK THE IlOYAI. ACADEMY OF SCIENCES 
ok tukin; foreign member ok the royai. society ok sciences ok 
GOTTINGEN, AND OP THE ROYAI. BOHEMIAN SOCIETY OK SCIENCES, AND 
OK THE ACADEMY OK THE I.INCEI OK ROME, AND OK THE AMERICAN 
ACADEMY OF ARTS AND SCIENCES OK BOSTON ; ASSOCIATE OK THE 
ROYAI. ACADEMY OK BEI.GIUM. HONORARY MEMBER OK THE 
NEW YORK ACADEMY OK SCIENCES, AND OK THE 
CAMBRIDGE P II II.OS O P II IC A I. SOCIETY, AND OK 
THE ROYAI. PIIYSICAI. SOCIETY OK EDIN- 
BURGH, AND OK THE 
BIOI.OGICAI. SOCIETY OK PARIS, AND OF THE CAI.IKOKNIA ACADEMY OK SCIENCES OK SAN FRANCISCO, AND 
OK THE ROYAI, ZOOLOGICAL AND M A I. A COI.O GIC A I. SOCIETY OK BELGIUM; 
CORRESPONDING MEMBER OK THE SKNKENBKRG ACADEMY OF PR AN KFU1IT- A- M ; 
FOREIGN ASSOCIATE OF THE NATIONAL ACADEMY OF SCIENCES. U.S.. AND MEMBER OK THE 
AMERICAN PHILOSOPHICAL SOCIETY ; 
HONORARY FELLOW OF THE RO Y A I. SOCIET Y OK EDINBURGH’, 
LATE DIRECTOR OF TIIK NATURAL HISTORY DEPARTMENTS OK TIIE BRITISH MUSEUM; I.ATF. PRESIDENT OK THE 
BRITISH ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE.' I.ATK KI'I.I. BRIAN PROFESSOR OK 
PHYSIOLOGY IN THE IlOYAI. INSTITUTION OK GBKAT BRIT AIN . 
LATE I.INACHK PROFESSOR OK COMPARATIVE ANATOMY AND FELLOW OF MERTON COLLEGE, OXFORD; 
EMERITUS PROFESSOR OK ZOOLOGY AND COMPARATIVE ANATOMY IN UNIVERSITY COLLEGE, UNIVERSITY OK LONDON 
WITH THE CO-OP 1C 11 ATI ON OF 
ADAM SEDGWICK, M.A., F.R.S., 
FELLOW OK TRINITY COLLEGE, CAMBRIDGE. AND PROFESSOR OF ZOOLOGY IN THE IMPERIAL COLLEGE OP 
SCIENCE AND TECHNOLOGY, LONDON; 
SYDNEY J. HICKSON, M.A., F.R.S., 
BKYRR PROFESSOR OK ZOOLOGY IN THE UNIVERSITY OP M A N C II K8 T E R ; 
E. A. MINCHIN, M.A., F.R.S., 
PROFESSOR OF PROTOZOOLOGY IN THE UNIVERSITY OK LONDON; 
AND 
GILBERT C. BOURNE, M.A., D.Sc., F.R.S., 
I, INACRE PROFESSOR OF COMPARATIVE ANATOMY, AND FELLOW OF MERTON COLLEGE, OXFORD. 
WITH LITHOGRAPHIC PLATES AND TEXT-FIGURES. 
LONDON. 
J. & A. CHURCHILL, 7 GREAT MARLBOROUGH STREET. 
1912. 
Adlard and Son, Impr.,] 
[London and Dorking 
