OF CONCHOLOGY. 161 



Q. 



Quadrangular, having four right an- 

 gles. 



Quadriplicated, having four plaits. 

 R. 



Radiate, furnished with rays. 



Radicated, is when the shell is fixed 

 by the base to another body. 



Rectangular, having right angles. 



Recurvated, turned backwards. 



Recurved, bowed back. 



Reflected, thrown backwards. 



Reflexed, the same as recurvated. 



Refracted, abruptly bent as if broken. 



Reniform, kidney-shaped. • 



Repand, with a serpentine margin. 



Replicated, folded or plaited, so as to 

 form a groove or channel. 



Reticulate, marked like a piece of 

 net work. 



Retroflected, bending in different 

 directions. 



Retuse, ending in an obtuse sinus ; 



bluntly notched. 

 Y 



