MOLLUSCA OP THE ' CHALLENGER ' EXPEDITION. 



529 



a little more attenuated behind ; pretty strong, puiished, trans- 

 lucent and white, with an opaque white band round the apex. 

 Sculpture none. Mouth large, straight ; edge thin and 

 chipped. Apical openiiifj small, straight, chipped, narrowed 

 inside by a minute shelf -like projecting ring. L. 0076. B. at 

 mouth 016, at broadest 0'035, at apex O'Ol. 

 It differs from C. ovulum, Phil., in being very much smaller, 

 rounder, and contracted into a tube at either end. 



'11. CaDULUS AMPULLACEUS, W. 



St. 24i. March 25, 1873. Culebra Island, St. Thomas, D. W. 

 Indies. 390 fms. Mud. 1 specimen. 



Shell. — Small, round, but not symmetrical in its two curves, con- 

 tracted in front, pinched in behind so as to form a short tube, 

 swollen, the fullest bulge lying behind the middle. Pretty 

 strong, polished and translucent white, with an opaque band 

 close to the apex. Sculpture none. Mouth large, very slightly 

 oblique ; edge thin and chipped. Apical opening slightly oval, 

 small, straight, roughened, narrowed inside by a flat, concentri- 

 cally puckered, and margined ring, which occupies nearly half 

 its diameter (0-014 and 0-006). The margin (about 001 thick) 

 of this ring is formed by the projecting end of a short pipe 

 (about 0-005 long) which passes up into the interior of the shell. 

 L. 0-08. B. at mouth 02, at broadest 0-047, at apex 0-016. 

 This species is not only much smaller than 0. ovulum, Ph., from 

 the Mediterranean, but is obviously very difi'erent in form and 

 proportions. It differs from C. exiguus, W., in being much 

 rounder, has no tube anteriorly, is not nearly so elongated poste- 

 riorly, and is provided with a distinct posterior pipe. 



LINN. JOTJRN— ZOOLOGT, VOL. XIV. 



39 



