239 
Grenus—POLYSTOMELLA. 
Sides equal, the last whorl embracing and concealing 
the previously formed one. 
P. Crispa Lam.—Macg. Aber. p. 33—NAUTILUS 
C. Lin 1162.—D. p. 341.—Gualt. ¢. 19. f. A. D.— 
Walk. f. 65.—Adams. t. 14. f. 30.—Mont. p. 187. 
§ Sup.t.18. f.5.—F. p. 228—Turt. D. p. 119.— 
With lateral spires, about twenty flexuous crenated joints 
in the exterior whor], marked with elevated striz outer 
edge carinated; interior volutions hidden ; aperture 
clasping the body, semicordate, furnished with a small 
perforation orsyphon. Kent, Dorset Devon, ¥c. Not 
uncommon, minute. 
P. Rorata.—Naovritus R. Maton in Lin. T. 8. p. 
114.—Turt. D. p. 118.—D. p. 340.—An Navti.us 
C. Lin 1162. ?— Mart. f. 180—Mont. p. 189. ¢. 15. 
f. 4. § Sup. p. 76.—F. p. 228.—Smooth. spiral, with 
six joints on the body whorl, marked by as many flexu- 
ous elevated striz radiating from the centre but not 
extending quite to the margin ; back strongly carinated, 
both sides equally convex, smooth and rather more 
elevated in the centre; inner volutions lost after 
entering the aperture, which is semicordate, clasping the 
