36 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 23 



the author some additional lots of unidentified material from the U. S. 

 National Museum. One lot comprised a number of single valves of C. 

 exquisitus taken April 7, 1888, at Albatross station 2813, off Hood 

 Island, Galapagos Islands, in 40 fathoms; Dall labelled the specimens 

 "Pseudamussium sp." 



Hancock Expeditions Collecting Stations: 

 GALAPAGOS ISLANDS: Albemarle, Barrington, Charles, Duncan, 



Gardner, Hood, James, and South Seymour Islands; 22 stations, 



12-150 fathoms, sand. 

 PERU: Callao; 210 fathoms, bottom sample 552 (dead). 

 COLOMBIA: 8 stations; Gorgona Island to Octavia Bay; 32-75 



fathoms. 

 PANAMA: Bahia Honda; 30-50 fathoms, bottom sample 332. 

 COCOS ISLAND, COSTA RICA: Chatham Bay; 30-50 fathoms, 



bottom sample 329. 

 GULF OF CALIFORNIA: 12 stations; Outer Gorda Bank, north to 



Angel de la Guarda Island ; 40-95 fathoms, rock, sand. 



Cyclopecten incongruus (Dall) 1916 

 Plate 13 



Pseudamusium incongruum Dall, 1916, p. 403. Albatross station 2986, 

 southwest of San Diego, in 684 fathoms. [Type labelled ". . . 

 station 2986, N.W. of Cerros Id." Cerros Island now Cedros 

 Island, Lower California.] 

 Pecten (Pseudamusium) incongruum Dall. Dall, 1921, p. 20. 



Holotype: U. S. National Museum. 



Type locality : Albatross station 2986, southwest of Cedros Island, 

 Lower California, Mexico. 



Original description: Shell small, white, suborbicular, left valve 

 rather flat with short straight hinge line, ears concentrically scaly, sculp- 

 ture of disk concentric continuous low sharp lamellae, crossed by slightly 

 raised radial lines, conspicuous only at the intersections which form in 

 the middle of the disk square reticulations with a small conspicuous 

 pustule at each intersection; laterally these are more crowded; right 

 valve concave near the margin, closely regularly concentrically lamellose ; 

 anterior ear with five radial lines, coarsely lamellose with a shallow notch 

 and serrate margin. Height, 14; breadth, 15; diameter, 3 mm. 



Remarks: This is the largest eastern Pacific Cyclopecten, none of 

 the other species exceeding 10 mm in height. It is very distinct, and is 

 known only from the type locality. 



