6£P 17 1917 



New Series, No. 203 (Vol. 51, Part 3). Price lOs. net. 



Subsci-iption per vokime (of 4 pai'ts) 40s. net. 

 AUGUST, 1907. 



THE 



QUARTERLY JOURNAL 



OP' 



MICROSCOPICAL SCIENCE. 



EDITED HY 



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



SUHAUY FELLOW UF EXKTEK COLLEGE, OXK 



AND OF TUE IMPKUIAL ACADEMY OF SCIK! 



OF SCIENCES OF F H I LADE L P II 1 A , A: 



OF Turin; foreign membkr o 



GOTTIXGEN, AND OF TUE UOYAL 



hd; cobrkspondent of tue institute of fb 



CES of ST. PETERSBURG, AND OF THE ACADEMY 

 D OF TUE ROYAL ACADEMY OF SCIENCES 



TUE ROYAL SOCIETY OF SCIENCES OP 

 BOHEMIAN SOCIETY OF SCIENCES, AND 



OF Tl: 



BIOLOGICAL SOCIETY 



ACADEMY OF TUE LINCEI OF ROME, AND OF Tl 



lY OF ARTS AND SCIENCES OF BOSTON ; ASSOCI 



AL ACADEMY OF BELGIUM; HONnRAIlY MEMBER 



NEW YORK ACADEMY OF SCIENCES, AND OF ' 



CAMBRIDGE P H ILOS U P U ! C AL SOCIETY, AND OF 



TUE ROYAL PHYSICAL SOCIETY OF EDIN* 



BURGU, AND OF TUE 



PARIS, AND OF TUK CALIFORNIA ACADEMY OF f 



FOREIGN ASSOCIATE OF TU: 



TUE , 



DIRECTOR OP TUE NATURAL HISTORY DEP.^ 



ASSOCIATION FOR THE ADV, 



PHYSIOLOGY IN 



\CES OF SAN FRANCISCO; 

 NATIONAL ACADEMY OF SCIENCES, U.S ., A N D MEMBER OF 

 MERICAN PUILOSOFHICAL SOCIETY ; 



RTMENTS OF TUE BRITISH MUSEUM; LATE PRESIDENT OF THE BRITISH 

 NCEMENT OF SCIENCK.; LATE KULLKRIAN PROFESSOR OP 

 THK ROYAL INSTITUTION OP GB EAT BRITAIN; 



VACBE PROFESSOR OF COMPARATIVE ANATOMY 



FELLOW OF MEBTON COLLEGE, OXFORD. 



WITH THE CO-OPEKAT]ON OF 



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



PROFESSOR OF ZOOLOGY AND COMPARATIVE ANATOMY IN TUE UNIVERSITY OF CAMBRIDGE; 



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



SSOR OF ZOOLOGY IN THE OWENS COLLEGE, ? 



AND 



E. A. MINCHIN, M.A., 



EVER PROFESSOR OF ZOOLOGY IN THE 0WEN3 COI.I-KG E, M AN CHESTK R ; 



AND 



PROFESSOR OF PROTOZOOIOGY IN' THE UMVEBSITV OF LONDON. 



WITH LITHOGRAPHIC PLATES AND TEXT-FIGUEES. 



^LOND 



ON 



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



1907. 



Adlard and Son, Impr.,] 



[London and Dorking. 



