(Continued frotn pnt/c S of eovvr.) 



VOLUME 52. 



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



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



2. Bridgman, p. AV. — The Velocity of Polymorphic Changes between Solids. 



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



