239 



GENUS POLYSTOMELLA. 



Sides equal, the last whorl embracing and concealing 

 the previously formed one. 



P. CRISPA LAM. Macg. Aber. p. 33 NAUTILUS 

 C.Lin I162.D.p.34l.Gualt. t.lV.f.A.D. 

 Walk.f. 65.~ Adams, t. 14. /. 30. Mont. p. 187. 

 fySup.t.lS.f.6. F. p. 22UTurt. D. p. 119. 

 With lateral spires, about twenty flexuous crenated joints 

 in the exterior whorl, marked with elevated striae outer 

 edge carinated ; interior volutions hidden ; aperture 

 clasping the hody> semicordate, furnished with a small 

 perforation or syphon. Kent, Dorset Devon, fyc. Not 

 uncommon, minute. 



F. ROTATA. NAUTILUS R. Maton in Lin. T. S.p. 

 lU.Turt.D.p. 118. D. p. 340. AN NAUTILUS 

 C. Linl\62.?Mart.f.l8QMont.p. 189. t. 15. 

 /. 4. fy Sup. p. 76. F. p. 228. Smooth, spiral, with 

 six joints on the body whorl, marked by as many flexu- 

 ous elevated striae 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 



