( Continued from page. 3 of cover. ) 



VOLUME 52. 



1. Thaxter, Roland. — New or Critical Species of Chitonomyces and Rickia. 



pp. 1-54. Jime, 1916. 70c. 



2. Bridgman, p. W. — The Velocity of Polymorphic Changes between SoUds. 



pp 55-88. July, 1916. 50c. 



3. Bridgman, P. W. — Polymorphism at High Pressures, pp. 89-187. July, 



1916. $1.00. 



4. Pierce, George W. — Theoretical Investigation of the Radiation Charac- 



teristics of an Antenna, pp. 189-252. , October, 1916. $1.00. 



5. Walton, A. C. — The 'Refractive Body' and the 'Mitochondria' of Ascaris canis 



Werner, pp. 253-266. 2 pis. October, 1916. 40c. 



6. Wilson, Edwin B., and Moore, C. L. E. — Differential Geometry of Two Dimen- 



sional Surfaces in Hyperspace. pp. 267-368. November, 1916. $1.50. 



7. Hitchcock, Frank Lauren. — A Classification of Quadratic Vectors, pp. 369—454. 



January, 1917. $1.25. 

 S. Wheeler, William Morton. — The Mountain Ants of western North America, pp. 



455-569. January, 1917. $1.25. 

 9. Bridgman, P. W. — The Electrical Resistance of Metals under Pressure, pp. 571-646, 



February, 1917. 90c. 



