COMPLETE GRAU : PECTINIDAE OF THE EASTERN PACIFIC 103 



Remarks: The validity of this subspecies has been questioned by 

 various authors. The criteria for separating the shell from that of the 

 typical would seem to be weaker than is usually required for the recog- 

 nition of subspecific rank, and gross anatomy studies by Dr. N. T. 

 Mattox and graduate student R. Kleinknecht of the Hancock Founda- 

 tion showed no apparent distinctions from the typical. However constant 

 differences in shell structure cannot be ignored and the subspecies is 

 geographically restricted, therefore the author feels that no change in 

 its status is advisable. 



Only one specimen of Chlamys circularis aequisulcata has been found 

 on the California coast during the past seven years, according to Mr. 

 John E. Fitch, research director of the California State Fisheries Labora- 

 tory at Terminal Island, San Pedro. In a recent conversation with 

 the author, Mr. Fitch said that he has been unable to find any others 

 in the course of his many field trips, and that marine laboratories, 

 fishermen and divers have also been unsuccessful. Although water 

 pollution is suspected of being a factor, no definite reason is known for 

 the near disappearance of this subspecies. 



Geographical range: Elkhorn Slough, Monterey Bay, California to 

 Bahia San Quintin, western Lower California. 



Geochronological range: Pleistocene, Recent. 



Bathy metric range : From several inches below surface at low tide to 

 about 25 fathoms, possibly deeper. 



Ecological data: Found on sand or mud bottoms, often in eel grass 

 beds; usually in bays or lagoons, also in quiet water just offshore. 



Hancock Expeditions Collecting Stations: 

 SOUTHERN CALIFORNIA AND SANTA BARBARA IS- 

 LANDS: 32 stations; from just below surface at low tide to 15 

 fathoms, sand or mud. 



Chlamys (Argopecten) purpurata (Lamarck) 1819 



Plate 34 



Pecten purpuratus Lamarck, 1819, p. 166. "Habite les mers orientales 

 et australes. . . . On le dit du Japon." [Eastern and southern seas. 

 . . . Reported from Japan.] 



Pecten purpuratus Lamarck. Conrad, 1831 [ex parte], p. 10, pi. 2, fig. 

 1. "Coast of Florida; also coast of Panama, and in Coquimbo Bay, 

 in Chile." [In synonymy: P. dislocatus Say (1822, p. 260); = 

 Ostrea gibba Linne, 1758, p. 698. Geographical range of O. gibba: 

 North Carolina to Florida; Gulf of Mexico, Caribbean Sea and 

 West Indies.] 



