MOLLUSCA OF THE ' CHALLENGEE* EXPEDITION. 525 



in the middle, and more drawn out before and behind ; it is 

 also straighter. Cadulus ventricosus^ Bronn, has the swelling 

 nearer the mouth. 



3. CADrLUS EASTEIDENS, W. 



St. 24. Mar. 25, 1873. Culebra Island, St. Thomas, Danish 



W. Indies. 390 fms. Mud. Many specimens. 



Shell. — Like the tooth of a rake, small, narrow, bent, swollen, 

 and on the convex curve very faintly angulated at about five 

 eighths of its length, from which point both the bend and the 

 narrowing of the shell is greater (proportionally) toward the 

 mouth than it is toward the apex. Between the back and the 

 belly there is a very slight compression of the shell. It is 

 pretty strong, brilliant, more or less obscurely banded trans- 

 versely, with alternate equal threads of opaque and transparent 

 white. Sculpture. Very faint, superficial, transverse scratches. 

 Mouth pretty large, not at all oblique, thin, sharp, and chipped ; 

 posterior opening round, straight; edge thickened, and less 

 chipped than the mouth. L. 0*119. B. at mouth 0*015, at 

 swelling 0*023, at apex 0*01. 



4. CADULrS SAIJEIDENS, W. 



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

 390 fms. Mud. 1 specimen. 



Shell. — Long, narrow, scarcely bent, swollen very slightly near 

 the middle of the convex curve, just perceptibly and a little 

 more anteriorly on the concave ; both the bend and the contrac- 

 tion are greater towards the apex than towards the mouth. 

 There is a very slight compression between the back and the 

 belly of the shell. It is thin, brilliant, scarcely opaque, white. 

 Sculpture. There is none, except perhaps some very faint 

 microscopic traces of longitudinal texture. Mouth rather 

 small, very oblique ; edge thin, but not chipped. Apical open- 

 ing small, straight across the shell, thin, chipped. L. 0*12. 

 B. at mouth 0*01, at -swelling 0*02, at apex 009. 

 This diff'ers from C. rastridens, "W., in being less bent, less 

 swollen, the swelling more central, more apparent on the ventral 

 curve ; the shell is less attenuated posteriorly, and more so ante- 

 tiorly ; there is no transverse sculpture ; the mouth here is 

 oblique, the shell at the anal opening is not thickened, and both 

 ends are narrower. Than C. gracilis, Jeffr., this is mucli smaller, 



