CONTENTS. 



Laws of the Society relating to the Transactions. iii 



Officers of the Society for the Year 1843. ..... T .. . v 



List of the Members of the Society elected since the Publication of the Seventh Volume. - vi 



Obituary Notice. ... - vii 



ARTICLE I. 



Contributions to Electricity and Magnetism. By Joseph Henry, LL. D. &c., Professor of 

 Natural Philosophy in the College of New Jersey, Princeton. 1 



ARTICLE II. 



Description of an entire Head and various other Bones of the Mastodon. By William E. 



Horner, M. D., and Isaac Hays, M. D. 37 



ARTICLE III. 

 On the Cecidomyia Destructor, or Hessian Fly. By Miss M. H. Morris. ... 49 



ARTICLE IV. 



Remarks on the Dental System of the Mastodon, with an Account of some Lower Jaws in 

 Mr, Koch's Collection, St. Louis, Missouri, where there is a solitary Tusk on the right 

 Side. By William E. Horner, M. D., Professor of Anatomy in the University of 

 Pennsylvania. 53 



VIII. — C 



