1896.] NATURAL SCIENCES OF PHILADELPHIA. 337 



This species superficially resembles closely the C. incanum of Key 

 West, but differs in the ovate form of the aperture, sculpture of the 

 earlier whorls, and the teeth of the aperture. 

 Cerion d'lplodon Pilsbry & Yanatta. PI. XI, fig, 26. 



Shell rather thin, cylindrical, the latter three whorls of about 

 equal diameter, those above slowly tapering to form a rather long, 

 convex cone. White, variegated with gray- white. Whorls lOI, 

 slightly convex, two nepionic smooth, those of the cone very finely, 

 sharply striate, the latter four with coarser riblets, much narrower 

 than their intervals. Umbilicus a short, compressed rimation. 



Aperture ovate, large and open, white, higher than wide. Per- 

 istome expanded and recurved, rather thick; axial fold basal; 

 parietal fold narrow, nearly a half whorl long ; an acccessory fold 

 ascends around the root of the columella, but at the apertural termi- 

 nation approaches close to the main parietal lamella. 



Alt. 29, diam. lOJ ; alt. of aperture 11 mm. 



Bahamas, exact locality unknown. 



This is an albino form of the Diacerion group, differing from C 

 rubicundum and its immediate allies in the greater distance between 

 the two parietal lamellae within. 



Plate XL 



Fig. 1. Cerion uva desculj^tum Pils. & Van. 



Fig. 2, 3. Cerion Yumaense Pils. & Van. 



Fig. 4. Cerion mumia magister Pils. & Van. 



Fig. 5. Cerion incrassatum microdon Pils. & Van. 



Fig:. 6. Cerion crassilabre Sallei Pils. & Van. 



Fig. 7. Cerion Blandi Pils. & Van. 



Fig. 8, Cerion multistriatum Pils. & Van. 



Fig. 9. Cerion tenuilabre pygmceum Pils. & Van. 



Fig. 10. Cerion hyperlissum Pils. & Van. 



Fig. 11. Cerion Abacoense Pils. & Van. 



Fig. 12. Cerion iostoviwn Arangoi Pils. & Van. 



Fiar. 13. Cerion Abacoense Bendalli Pils. & Van. 



Fiff. 14. Cerion iostomum Pfr. 



Fig. 15. Cerion incanoides Pils. & Van. 



Fig. 16. Cerion sarcostomum Pils. & Van. 



Fig. 17. Cerion columna Pils. & Van, 



Fig. 18. Cerion columna validum Pils. & Van. 



Fig. 19, 20. Cerion Eleutherce Pils. & Van. 



