GEOGRAPHICAL 
Mopalia Hindsii Gray. 
Str. Fuca to Monterey. 
Mopalia Simpsonii Gray. 
San Francisco, California. 
Mopalia vespertina Gid. 
Str. Fuca to Monterey, Cal. 
Mopalia lignosa (id. 
Str. Fuca to Monterey—Sitka. 
Mopalia acuta Cpr. 
“Monterey,” (Nuttall coll.) 
Mopalia? sinuata Cpr. 
Str. Fuca, W. T. 
Mopalia? imporcata Cpr. 
Str. Fuca, W. T. 
Acanthopleura scabra Pv. 
Str. Fuca to Santa Barbara. 
Acanthopleura fluxa Cpr. 
Catalina I., or Santa Barbara I., Cal. 
Ischnochiton Magdalensis Huds. 
Monterey to San Diego—Lower Cal. 
Ischnochiton veredentiens (pr. 
Monterey, or islands off South California, 
Lepidopleurus regularis Cpr. 
Monterey or southward. 
Lepidopleurus scabricostatus Cpr. 
Catalina I., 20 fms., rare. 
Lepidopleurus pectinatus Cpr. 
Catalina I., 1. w., rare. 
Lepidopleurus Mertensii Midd. 
Str. Fuca to Monterey. 
Trachydermon retiporosus (pr. 
Str. Fuca, W. T. 
Trachydermon interstinctus (id. 
Puget’s Sound to Monterey. 
Trachydermon trifidus Cpr. 
Str. Fuca, W. T. 
Trachydermon dentiens (id. 
Puget’s Sound, W. T.? 
Trachydermon pseudodentiens Cpr. 
Str. Fuca, W. T. 
Trachydermon gothicus Cpr. 
Catalina I., 20 fms., 1. w. 4 
Trachydermon Hartwegii Cpr. 
San Francisco to Monterey. 
CATALOGUE 
