CONTENTS. 
Officers of the Society for the year 1863, c : : : 
List of the members of the Society elected since the publication of Te Bleventh volume, . 
List of the members reported deceased since the publication of the last volume, 
Laws of the Society relating to the Transactions, 
12) AS 15) Pde 
ARTICLE I. 
On the Geology and Natural History of the Upper Missouri. By F. V. Hayden, M.D., 
ARTICLE II. 
Experiments and Observations upon the Circulation in the Snapping Turtle (Chelonura Serpentina), with 
especial reference to the Pressure of the Blood in the Arteries and Veins. By S. Weir Mitchell, M.D., 
Baie? Wi ots Ripa! Gil OF 
ARTICLE III. 
On the Hthnography and Philology of the Indian Tribes of the Missouri Valley. By F. V. Hayden, M.D., 
PARE fT TE: 
ARTICLE IV. 
Intellectual Symbolism: A Basis for Science. By Pliny Harle Chase, M.A., 
231 
463 
