PREFACE 



The material in the Allan Hancock Foundation contains a very 

 valuable collection of marine mollusks from the Pacific coast of America. 

 I am extremely grateful that I have been allowed to work out the 

 family Arcidae and present the result of my work in this paper. 



I beg herewith to render my best thanks to Captain Allan Hancock 

 and the Research Committee of the Allan Hancock Foundation for 

 giving me the opportunity to work as a Research Fellow of the Founda- 

 tion. 



I wish also to express my thanks to the following members of the 

 Allan Hancock Foundation staff: the editor, Mrs, Dorothy M. Hal- 

 mos, to whom I am extremely indebted for her help in preparing the 

 paper for publication ; Dr. Norman T. Mattox, who placed the material 

 in my hands and helped me in different ways during the work; Miss 

 Janet Haig, who kindly corrected my manuscript; Mr. Gaylen C. 

 Hansen, who with great interest and care made the drawings ; and Mr. 

 Roy V. George, who made the photographs for the plates. I am also 

 indebted to Dr. S. Stillman Berry, Redlands, Dr. Leo G. Hertlein, 

 California Academy of Sciences, Dr. A. Myra Keen, Stanford Univer- 

 sity, and Mr. E. P. Chace, San Diego Museum of Natural History, for 

 the use of their collections for comparison. I also wish to thank Dr. E. 

 Reilly, New York State Museum, Albany, for his efforts in trying to 

 locate some of Carpenter's specimens. For discussion and supervision, I 

 am greatly indebted to my principal, Director Tron Soot-Ryen, of 

 Troms^ Museum, Norway. 



[177] 



NOV 1 5 1955 



