NO. 2002. DIAGNOSES OF NEW PACIFIC SHELLS— BALL. 597 



rior more pointed; interior polished, the muscular scars perceptible, 

 small; hinge small and weak, constructed of two feeble laterals in 

 each valve and a median internal resUium. Length of shell, 7; of 

 anterior part, 4; height, 6; diameter, 2 mm. 

 With the last. Cat. No. 214445, U.S.N.M. 



ALIGENA NUCEA, new species. 



Shell small, white, rather solid, ovate, slightly inequilateral, mod- 

 erately inflated; surface rather rude, with irregular, rather coarse 

 incremental lines; beaks full, somewhat posterior, the anterior end 

 of the shell shorter; interior porcellanous, the muscular scars unusu- 

 ally large, the pallial line irregular, entire; hinge with a long, strong, 

 narrow, chondrophore, a small pustular projection in front of it, as 

 usual in the genus. Length of shell, 4.0; of anterior portion, 1.75; 

 height, 3.0; diameter, 2.2 mm. 



Gulf of California. Cat. No. 267149, U.S.N.M. 



This species recalls A. cokeri Dall, of Peru, but wants the median 

 radial depression and has a proportionately stronger hinge. 



VESICOMYA (ARCHIVESICA?) SUAVIS, new species. 



Shell oval, white, with an elegantly polished, minutely concentric- 

 ally sparsely lamellose periostracum, smoother near the beaks; equi- 

 valve, inequilateral, the beaks nearer the anterior end; there is no 

 lunule, but a long lanceolate depression radiating from the beaks, 

 bordered on each side by an obscure radial rib, simulates an escutcheon 

 though not defined by any incised line; shell moderately inflated, the 

 beaks full but low and prosocoelous; the ligament external, strong, 

 and conspicuous ; the two ends of the shell subequal and rounded, the 

 anterior end a little smaller; interior chalky, with large adductor 

 scars and an entire pallial line; hinge like that of V. gigas but less 

 developed; length of the shell, 34; of the anterior part, 10; height, 

 22; diameter, 13 mm. 



West of Tiburon Island, Gulf of California, in deep water. Cat. 

 No. 266881, U.S.N.M. 



This species, by the shell, belongs to the group of V. lepta and gigas, 

 but the soft parts being unknown its place must remain uncertain. 



