VI CONTENTS 



Page 

 The glacial history of an extinct volcano, Crater Lake National Park, by 



WaUace W. Atwood, Jr 303 



Concretions — freaks in stone, by R. S. Bassler 321 



Biology and human trends,' by Raymond Pearl 327 



The relation of genetics to physiology and medicine, by Thomas Hunt 



Morgan 345 



Conservation of the Pacific halibut, an international experiment, by 



William F. Thompson 361 



The swallowtail butterflies, by Austin H. Clark 383 



Those ubiquitous plants called algae, by Florence E. Meier 409 



The Boulder Canyon project, by Wesley R. Nelson 429 



Wings over the sea, by Louis Bleriot 453 



The coming of man from Asia in the light of recent discoveries, by Ales 



Hrdlicka. 463 



The antiquity of man in America in the light of archeology, by N. C. 



Nelson 471 



A survey of southwestern archeology, by Frank H. H. Roberts, Jr 507 



Nuzi and the Hurrians: The excavations at Nuzi (Kirkuk, Iraq) and their 



contribution to our knowledge of the history of the Hurrians, by 



Robert H. Pfeiflfer 535 



The ruins of Tenampua, Honduras, by Dorothy H. Popenoe 559 



