THE 



ORIGIN OF VERTEBRATES 



BY 



WALTER HOLBROOK GASKELL 



M.A., M.D. (CANTAB.), LL.D. (EDIN. AND McGILL UNIV.) ; F.R.S. ; FELLOW OF TRINITY 

 HALL AND UNIVERSITY LECTURER IN PHYSIOLOGY, CAMBRIDGE ; HONORARY FELLOW 

 OF THE ROYAL MEDICAL AND CHIRURGICAL SOCIETY; CORRESPONDING MEMBER 

 OF THE IMPERIAL MILITARY ACADEMY OF MEDICINE, ST. PETERSBURG, ETC. 



LONGMANS, GREEN, AND CO 



39 PATERNOSTER ROW, LONDON 



NEW YORK, BOMBAY, AND CALCUTTA 



1908 



All rights reserved 



