OF CONCHOLOGY. 117 



Fig. 11th.— NAUTILUS SPIRU- 



LA. Aperture of the shell orbicular ; 

 whorls cylindrical, separated, and gra- 

 dually decreasing inwards, the first a 

 little straight siphunculus contiguous 

 to the walls of the shell ; outside of a 

 pale cream colour, within pearlaceous. 



Inhabits the American and Indian 

 oceans. 



Linn. Syst. Naturae, page 1163. 



Turton's Linne, vol. 4th, page 307. 



N Spicula^ V siphunculus, WWW 

 WW chambers. 



Fior. 12th -TURBO COSTATUS. 

 Shell sub-pellucid, white and sub- 

 turrited ; volutions five, with promi- 

 nent, longitudinal ribs, a little oblique ; 

 apex obtuse ; aperture sub-orbicular, 

 with a thick sulcated margin. 



Found in Pembrokeshire, Dorset- 

 shire, and Northumberland. 



Linn. Trans, vol. viii. page 174. 



RRRR Ribs. 



