KEYS TO THE VARIOUS GROUPS. 33 



KEYS TO THE VARIOUS GROUPS. 



In" using the following keys the student has only to keep 

 in mind three points : 



1. That there are always two contrasting alternates to 

 choose from (occasionally three). 



2. That these alternates are marked by similar initial 

 letters, A, B, c, d, etc., and by similar indentation on the 

 page, and distinguished by superior numerals. A", B^, c^, 

 etc. 



3. That the contrasting alternate is the nearest line in 

 the same set which begins with the same indentation and 

 the same initial letter, though with a different numeral. 



For example, in the first table, the A' on p. 34 has its 

 alternate A", which is a long way off (on p. 42), but is never- 

 theless the next line beginning with an A, and it has the 

 same indentation, while D' on p. 34 is immediately followed 

 by D'. 



When alternates relate, one or the other or both of them, 

 to tribes or higher groups, an initial capital is prefixed ; 

 when both refer to genera, or pairs of genera, a small letter 

 is prefixed. The final terms are the numbered genera. 



For the explanation of the numbered veins in the first 

 table, see the figure on p. 60. 



