COLUMBIA UNIVERSITY BIOLOGICAL SERIES. II. 



AMPHIOXUS AND THE ANCESTRY 

 OF THE VERTEBRATES 



BY 



ARTHUR WILLEY, B.Sc. 



TUTOR IN BIOLOGY, COLUMBIA COLLEGE; BALFOUR STUDENT OF THE 

 UNIVERSITY OF CAMBRIDGE 



WITH A PREFACE 



BY 



HENRY FAIRFIELD OSBORN 



MACMILLAN AND CO. 



AND LONDON 

 1894 



All rights reserved 



