9z 

 THE NERVOUS SYSTEM '^T^ 



OF VERTEBRATES 



BY 



J. B. JOHNSTON, Ph. D. 



PROFESSOR OF ZOOLOGY IN WEST VIRGINIA UNIVERSITY 



With One Hundred and Eighty Illustrations 



PHILADELPHIA 



P. BLAKISTON'S SON h CO, 



1012 WALNUT STREET 

 1906 



