2l 



QUAR^rERLY JOURNAL 



MICIIOSCOPICAL SCIENCE. 



EDITED BT 



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



HO.\OKAKY KKLLOW OF EXETER COLLEGE, OXfOBD ; CORRESPONDENT OF THE INSTITUTE OF FRA^ 



AND OF THE IMPERIAL ACADEMV OF SCIENCES OP ST- PETERSBURG, AND OF THE ACADEMY 



OF SCIENCES OF PHILADELPHIA; FOREIGN MKMBBR OF THE ROVAL BOHEMIAN 



SOCIETY OF SCIENCES, AND OF THE ACADEMY OP THE LINCEI OF ROME; 



ASSOCIATE OF THE ROVAL ACADEMY OP BELGIUM; HONORARY MEMBER 



OF THE NEW YORK ACADEMY OF SCIENCES, AND .)F THE 



CAMBRIDGE PHILOSOPHICAL SOCIETY, AND OF THE ROYAL 



PHYSICAL SOCIETY OF EDINBURGH ; HONORARY 



MEMBER OF THE BIOIOGICAL SOCIETY 



OF PARIS; 



DIRECTUK ofr THE NATURAL HISTORY DEPARTMENTS OF THE BRITISil MUSKIj'M; LATE FULLFRIA> 



FROFE^SOK OF PHYSIOLOGY IN THE ROYAL INSTITUTION OF Gi; EAT BKtTAIN- 



WITH THE CO-OPEUATION OF 



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



FELLOW AND TUTOR OF TRINITY COLLEGE, CAMBRIDGE; 



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



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



BKYKR FROFKSSOII OF ZOOLOGY IN TIIK OWENS roM.KGK, 3IANCUESTKH. 



VOLUME 44.— New Series. 

 W\\.\ I'itl^ogrHpljit |)lat£s nnb (Irngrabings on 8$loob. 



^LONDON: 



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



1901. 



