( Cotit!ime<l from paflP .9 of roiwr, ) 



VOLUME 52. 



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



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



2. Bkidgman, p. W. — Tlie Velocity of Polymorphic Changes between Solids. 



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



3. Bridgman, p. W. — Poiymorphi.sm at High Pressures, pp. 89-187. July, 



1916. $1.00. / • 



