162 THE ELEMENTS 



Retundated, blunted, or turned at 



the edge. 

 Reversed spire, is when the volutions 



are the reverse way of a common 



cork screw. 

 Reversed spires, when the spires are 



turned upwards. 

 Revolute, rolled backwards. 

 Ribbed, longitudinal, an( j sometimes 



7 C 



transverse ridges. 



Ridge, the upper part of a slope. 



Rima,theinterstice between the valves, 

 when the hymen is removed. 



Rostrated, having a beak; the exten- 

 sion of the shell, in which the canal 

 is situated. 



Rotund, round, circular, spherical. 



Rudiment, the first part of a thing; 

 generally applied to the indistinct 

 teeth of shells. 



Rufous, of a reddish colour. 



Rugose, rugged, full of wrinkles. 



