GENUS XXX. MERITA. 133 



no umbilicus ; the aperture entire and half round ; the 

 pillar nearly transverse, with an acute and generally den- 

 tated edge (see Nerita polita, pi. 9. /. 119). 

 Natica. Shell nearly globular, umbilicated, the left lip thick 

 towards the umbilicus ; the aperture entire and half round ; 

 the pillar oblique, without teeth (see Nerita Canrena, 

 p/. 9. /. 118). 



