Plate 9 



Fig. 1. Chione fluctifrac/a Sowerby : Hard-shell cockle. San Diego. Natural 

 size. Exterior left valve. 



Fig. 2. Chione undateUa Sowerla.v ; Hard-.shell cockle. Anaheim Slough. Natural 

 .size. Exterior riglit valve. 



Fig. 3. Chione sueeincta Valenciennes; Hard-shell cockle. Anaheim Slough. 

 Natuial size. Exterior riglit valve. 



Fig. 4. Chione siiceincta. same specimen as Fig. 3. Interior left valve. 



