THE AMERICAN JOURxNAL 



OF 



ANATOMY 



EDITORIAL BOARD 



CHARLES R, BARDEEN GEORGE S. HUNTINGTON, 



L'niversity of Wisconsin. Columbia University. 



HENRY H. DONALDSON, FRANKLIN P. MALL, 



The Wistar Institute. Johns Hopkins University. 



THOMAS DWIGHT, J. PLAYFAIR McMURRICH, 



Harvard University. Iniversity of Toronto. 



SIMON H. GAGE, CHARLES S. MINOT, 



Cornell University. Harvard University. 



G. CARL HUBER, (JEORGE A. PIERSOL. 



University of Michigan. University of Pennsylvania. 



■ KEI# ^Y McE. KNOWER, Secretary, 

 JoMis Hopkins University. 



VOLUME IX 



I^UBLISHED QUARTERLY BY 



THE WISTAR INSTITUTE OF ANATOMY AND BIOLOGY 



36th street and WOODLAND AVENUE 



PHILADELPHIA, PA. 



