( Continued from page 3 of cover. ) 



VOLUME 52. 



1. Thaxter, Roland. — New or Critical Species of Chitonomyces and Rickia. pp. 1-54. 



June, 1916. 70c. 



2. Bridgman, p. W. — The Velocity of Polymorphic Changes between Solids, 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 Characteristics 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 Dimensional 



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. 

 ■8. 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. 



10. Thaxter,' Roland. — New Laboulbeniales, chiefly Dipterophilous American Species. 



pp. 647-721. May, 1917. $1.00. 



11. Crozier, W. J. — On the Pigmentation of a Polyclad. pp. 723-730. 1 colored plate. 



May, 1917. 40c. 



12. Trueblood, H. M. — The Joule-Thompson Effect in Superheated Steam: I. Experi- 



mental Study of Heat-leakage, pp. 731-804. June, 1917, $1.00. 



