148 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL, 23 



Geochronological range: Miocene (?), Pliocene, Pleistocene, Re- 

 cent. 



Bathy/netric range: 20 to 100 fathoms (possibly deeper). 

 Ecological data : Found in sand or mud bottoms. 

 Hancock Expeditions Collecting Stations: 

 OREGON: 20 to 76 fathoms, sand or mud; sta. 1471-42, 1481-42, 

 1497-42 (43° 37' 40" N to 44° 50' 45" N; 124° 15' 53" W to 

 124° 22' 22" W). 



Subgenus OPPENHEIMOPEGTEN von Teppner 1922 



O ppenheimopecten von Teppner, 1922, p. 254. [Proposed as a subgenus 

 of Philip pia von Teppner, 1922, p. 221.] Type species: Pecten 

 suhhenedictus Fontannes, 1878, p. 99, pi. ii, fig. 1; type locality: 

 Miocene of the Visan Basin, Vaucluse, France. 

 Convexopecten Tucker-Rowland, 1938c, p. 82. [Proposed as a subgenus 

 of Pecten.\ Type species: Pecten Josslingii Sowerby in J. Smith, 

 1847, pp. 413, 419, pi. 16, figs. 10-12; type locality: Upper Ter- 

 tiary of River Tagus, Portugal. 

 Original diagnosis: Ungleichklappig, rechte Schale stark convex 

 (Wirbel stark eingekriimmt) mit gerundeten Rippen, breiter als die 

 Zwischenraume. Ohren gross, ungleich. Rippen der linken Schale flach 

 und breit, schmaler als die Zwischenraume. Konzentrische Verzierung 

 der rechten Schale sehr schwach, der linken deutlich. (von Teppner in 

 Roger, 1939.) 



Translation: Inequivalve, right valve strongly convex (umbo strong- 

 ly incurved) with rounded ribs, broader than the interspaces. Ears large, 

 unequal. Ribs of left valve flat and broad, narrower than the interspaces. 

 Concentric sculpture of right valve very weak, the left distinct. 



Additional diagnosis: Of the above criteria, the most important are 

 the strongly convex right valve and strongly "incurved" umbo, the 

 latter being also strongly inflated. The left valve is shallowly to moder- 

 ately concave, the size of the auricles of the right valve in relation to 

 that of the disk is variable and the ribs of the left valve may be rather 

 round. 



Rernarks: This subgenus effectively separates the forms having deep- 

 ly convex right valves with inflated umbos and varyingly concave left 

 valves from such groups as those of Pecten maxirnus (Linne) and 

 P. jacobaeus (Linne). 



