248 



REPORT ON ALBATROSS MOLLUSCA— DALL. 



DESCRIPTIONS OF THE SPECIES. 



Order PRIONODESMACEA. 



Suborder PECTINACEA. 



Family PECTINIDiE. 



Genus PECTEN Miiller. 



Pecten glyptus Verrill. 



Plate vin, Figs. 2, 3. 



Pecten glyptus Verrill, Trans. Conn. Acad. Sci., v, p. 580, July, 1882. 

 Fecten Tryoni Dall, Bull. Mus. Cornp. Zoology, xvm, p. 438, June, 1889. 



west longitude 75° .33', off the coast of North Carolina in 124 fathoms, 

 sand ; bottom temperature 61° F. ; and off Martha's Vineyard in 85 to 

 120 fathoms. 



Shell large, thin, both valves about equally convex, right valve more 

 brilliantly colored; ears subequal, hinge line straight; beaks small, 

 pointed, not prominent; orb of the shell somewhat oblique, anterior por- 

 tion produced downward and forward, margin simple, entire, sharp ; sculp- 

 ture of wide little-elevated ribs, about seventeen in number, each with 

 a central keel which is sharp and slightly serrate over two-thirds of the 

 surface but becomes obsolete toward the margin; this keel is colored 

 more deeply than the rest of the rib, and the color may be alternately 

 concentrated at the prominences and fainter between them. In the 

 specimens observed it is either deep rose color or a warm orange-brown, 

 fading gradually on each side of the keel of the ribs, while the inter- 

 spaces are pale or white, with faint narrow radiating lines of the color; 

 on the right valve, except along the hinge line, the auricles are pale; 

 the minute sculpture consists, on this valve, of fine radiating grooves, 

 about a dozen between the carina? of each pair of ribs, across which are 

 carried in fine scallops sharp little-elevated lamellae; these lamellae are 

 easily felt, but visible only with some magnification; the left valve 

 shows (in a rose-colored specimen) very little color, and that a mottled 

 orange-brown confined chiefly to the ribs of the apical third; the ribs 



