ZOOLOGICAL ARTICLES 



CONTRIBUTED TO THE "ENCYCLOPEDIA BRITANNICA" 



BY 



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



DEPUTY LINACRE PROFESSOR IN THE UNIVERSITY OF OXFORD, AND HOK. FELLOW OF EXETER COLLEGE 

 PRESIDENT OF THE MARINE BIOLOGICAL ASSOCIATION OF THE UNITED KINGDOM ; 



HON. MEMBER OF THE CAMBRIDGE PHILOSOPHICAL SOCIETY; 

 CORRESPONDING MEMBER OF THE ACADEMY OF SCIENCES OF PHILADELPHIA. 



TO WHICH ARE ADDED KINDRED ARTICLES BY 



W. JOHNSON SOLLAS, LL.D., F.R.S. 



PROFESSOR OF GEOLOGY IN TRINITY COLLEGE, DUBLIN. 



LUDWIG VON GRAFF, PH.D. 



I'ROFESSOR OF ZOOLOGY IN THE UNIVERSITY OF GRAZ, AUSTRIA. 



A. A. AV. HUBRECHT, PH.D., LL.D. 



PROFESSOR OF ZOOLOGY IN THE UNIVERSITY OF UTRECHT. 



A. G. BOURNE, D.Sc. 



PROFESSOR OF BIOLOGY IN THE PItESIDENCY COLLKGF-, MADRAS. 



W. A. HERDMAN, D.Sc. 



PROFESSOR OF NATURAL HISTORY IN THE UNIVERSITY COLLEGE, LIVERPOOL. 



EDINBURGH: ADAM & CHAELES BLACK 

 NEW YORK: CHARLES SCRIBNER'S SONS 



MDCCCXCI 



