QUARTERLY JOURNAL 



OF 



MICROSCOPICAL SCIENCE. 



EDITED BY 



E. EAY LANKESTER, M.A., LL.D., F.R.S., 



nONOKAUY FELLOW OF EXETER COLLEGE, OXFORD ; CORRESPONDENT OF THE INSTITUTE OF FRANCE, 



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



OF SCIENCES OF PHILADELPHIA; FOREIGN MEMBER OF THE ROYAL BOHEMIAN 



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



ASSOCIATE OF THE ROYAL ACADEMY OF BELGIUM ; HONORARY MEMBER 



OF THE NEW YORK ACADEMY OF SCIENCES, AND OF THE 



CAMBRIDGE PHILOSOPHIC AL SOCIETY, AND OF THE ROYAL 



PHYSICAL SOCIETY OF EDINBURGH ; HONORARY 



MEMBER OF THE BIOLOGICAL SOCIETY 



OP PARIS i 



DIRECTOR OF THE NATURAL HISTORY DEPARTMENTS OF THE BRITISH MUSEUM; FULLERIAN PROFESSOR 



itV PHYSIOLOGY IN THE ROYAL INSTITUTION OF GREAT BRITAIN. 



WITH THE CO-OPERATION OF 



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



FELLOW AND TUTOR OP TRINITY COLLEGE, CAMBRIDGE; 



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



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



BKVF.R PROFESSOR OF ZOOLOGY IN THE OWENS COLLEGE, MANCUESTKR. 



VOLUME 43.— New Series. 



LONDON: 

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



1900. 



i 



