

CONTENTS 



1. A Report on the Family Mytilidae (Pelecypoda) 



(Plates 1-10; text-figures 1-78), by Tron Soot-Ryen . 1-176 



2. A Report on the Family Arcidae (Pelecypoda) 



(Plates 11-16; text-figures 79-95), by Helen Rost . . 177-250 

 In^ex 251-261 



fiMITHSOiw,... MAP 9 .1 «A^ 

 IMSTITUTION MAR 2 4 1860 



