320 
University of California Publications in Zoology [Vou. 13 
SPECIES OCCURRING IN GRouUP 1: PurRE Mup 
Cardium corbis 
Macoma balthica* 
Macoma nasuta* 
Mya arenaria* 
Mya california* 
Mytilus edulis* 
Ostrea lurida 
Paphia staminea 
Pholas pacificus 
Psephidia ovalis 
Zirfaea gabbi 
Epitonium hindsi 
Odostomia franciscana 
Turbonilla franciscana 
SPECIES OCCURRING IN GROUPS 2 AND 4: Mup AND SAND 
Cardium corbis* 
Gemma gemma yar. purpura* 
Macoma balthica* 
Macoma inquinata 
Macoma nasuta* 
Mya arenaria 
Mya california* 
Mytilus edulis* 
Ostrea lurida 
Phacoides tenuisculptus* 
Pholas pacificus 
Psephidea ovalis 
Schizothaerus nuttalli 
Solen sicarius 
Tellina buttoni* 
Tellina salmonea* 
Zirfaea gabbi* 
Crepidula niva* 
Columbella gausapata 
Nassa mendica 
Nassa fossata* 
Nassa perpinguis 
Thais lamellosa* 
Turbonilla franciscana 
SPECIES OccURRING IN GRouUP 3: MupD AND SHELLS 
Cardium corbis 
Gemma gemma var. purpura* 
Macoma inquinata 
Macoma nasuta* 
Mya arenaria* 
Mya california* 
Modiolus, ef. rectus 
Mytilus edulis 
Ostrea lurida 
Paphia staminea 
Psephidea ovalis 
Zirfaea gabbi* 
Columbella gausapata 
Epitonium hindsi? 
Nassa fossata? 
Nassa mendica* 
Thais lamellosa 
Turbonilla keepi 
SPECIES OCCURRING IN GRouP 5: PuRE SAND 
Mytilus edulis* 
Phacoides tenuisculptus* 
Psephidea ovalis* 
Tellina buttoni* 
Turbonilla franciscana* 
SPECIES OccURRING IN GRouP 6: SAND AND GRAVEL 
Cardium corbis 
Hinnites giganteus 
Macoma balthica 
Macoma inquinata 
Macoma nasuta 
Monia macroschisma 
Mya california 
Ostrea lurida 
Saxidomus nuttalli 
Schizothaerus nuttalli 
Spisula eatilliformis 
Tellina salmonea* 
Nassa fossata 
Thais Jamellosa 
Zirfaea gabbi 
SPECIES OccURRING IN GROUP 7: SAND AND SHELLS 
Cardium corbis 
Macoma balthica 
Macoma inquinata 
Macoma nasuta 
Mya arenaria 
Mya ealifornia* 
Mytilus edulis 
Ostrea lurida 
Psephidia ovalis* 
Schizothaerus nuttalli 
Tellina salmonea 
Zirfaea gabbi 
Epitonium hindsi* 
Epitonium savinea 
Nassa perpinguis 
Thais lamellosa 
Turbonilla keepi 
