154 WHERRY AND ADAMS: CLASSIFICATION OV MIMETIC CRYSTALS 



compounds. The subdivisions arc, it should be noted, not 

 mutually exclusive, and one crystal may fall simultaneously 

 into two or more of them, although usually most typical of one. 

 The names of the crystal systems and classes used are drawni 

 largely from Dana, with the following exceptions: cubic in place 



TABLIC I. 

 Types of Mimetic Phenomena, with Prefixes Proposed, and Illustrations 



General prefixes for the whole group { 



{ for original class, homo- (same) 



of isometric; trigonal as a distinct system; and rhombic in place 

 of orthorhombic. No changes in the plans of nomenclature here 

 proposed will need to be made should the use of other names be 

 preferred. 



DISCUSSION OF TABLE I 



Whenever it is desired to refer to mimetic behavior without 

 considering the cause or effect as such, the prefixes homo- and 

 pseudo-, signifying, respectively, "the same" and "false," may be 

 used. For instance, the crystallization of the aragonite group 

 may be described as "homo-rhombic but pseudo-hexagonal." 



