366 PROCEEDINGS OF THE ACADEMY OF [1897. 



Typical C. Forclii exactly resembles externally a coarsely sculpt- 

 ured form of G. Dalit from Inagua; but it has the internal armature 

 of Strophiops or Maynardia. It is a coarser, larger shell than C. 

 eximeum of Cat Island and New Providence, with far stronger 

 development of peristome and teeth and more interrupted strigation. 

 C. Fordii has not the raised ledge across the parietal wall of C. 

 glans varium, from New Providence, has stronger peristome and 

 teeth, and is larger. 



The pure white form C. Fordii resembles C. abacoense, but is less 

 stout in the average, has a liver-tinted mouth and lip, and the parie- 

 tal tooth is notably longer and stronger. 



Var. submarmoratum is a larger shell than C. marmoratum, 

 stouter above, and with a much more developed parietal tooth. It 

 has not the expanded umbilical area of C. regina eucoxmium, of 

 Turk's Island. 



White specimens of this variety are very similar to C. eleutherce, 

 but do not taper gradually as that species, the angle of obliquity of 

 the aperture is different, etc. 



Several hundreds of this species were obtained by Mr. John Ford 

 from a barrel of shells from the Bahamas, exact island unfortunately 

 unknown. On comparison with the nearly complete series of Cer- 

 ion in the collection of the Academy it is evident that a new poly- 

 morphic species is before us, probably from an island or region of 

 an island hitherto unexplored for this genus. Both the striate and 

 smooth forms occurred either white or strigate, and so far as we 

 can judge in nearly equal numbers. Transition forms are fully 

 represented, though probably 95 per cent, of the specimens are either 

 the one or the other. 



Cerion Pillsburyi P. & V. Fig. 5. 



Shell tapering subcylindrical, the later three whorls of nearly 

 equal diameter, those above forming a rather long cone, which 

 passes very gradually into the subcylindrical portion ; apex very 

 obtuse. Whorls 10 to KH, the nepionic smooth, next whorl sharply 

 finely striate or smoothish ; all succeeding whorls except the last one- 

 half to two, flat and smooth with some growth-lines only ; last one- 

 half to two whorls regularly costulate, riblets narrower than the 

 intervals, about one millimeter apart. Base rounded, not com- 

 pressed ; umbilical chink very short, imperforate. White with irre- 

 gular, interrupted brown or gray-brown streaks. 



