I^ r CONTENTS. 



Nurober 104. 



Page 

 Art. XIV. — Ratio of Radium to Uranium in some Minerals ; 



by B. B. Boltwood 97 



XV.— Constitution of Hydrous Thallic Chloride ; by F. M. 



McClenahan _ _ __..».. _ _ 104 



XVI. — Study of tbe Structure of Paleozoic Cockroaches, 

 with Descriptions of New Forms from the Coal 

 Measures; by E. H. Sellards. (With Plate I and. 

 . thirty-seven figures in the text) . 113 



XVII. — Remarkable Parasite from the Devonian Rocks of 



the Hudson Bay Slope ; by W. A. Parks 135 



XVIII. — Asterolepicl Appendages; by C. R. Eastman 141 



XIX. — Electrotropism of Roots ; by A. B. Plowman. (Pre- 

 liminary Communication) 145 



XX.— Oxygen Absorption Bands of the Solar Spectrum ; by 



O. C. Lester. (With Plates II, III and IV) 147 



SCIENTIFIC INTELLIGENCE. 



Geology and Natural History — United States Geological Survey, 157. — 

 Alaska, Glaciers and Glaciation, G. K. Gilbert, 159. — Origin and Bela- 

 tionship of the large Mammals of North America and the Caribou, M. 

 Grant : Mammals of Pennsylvania and New Jersey, S. N. Ehodes : 

 Medusas of the Bahamas, A. G. Mayer, 161. 



Miscellaneous Scientific Intelligence— International Congress of Arts and 

 Science at the Universal Exposition, St. Louis : Geographen Kalender, 

 1904-1905, H. Haack, 162. 



Obituary — John Bell Hatcher, 163. 



