368 PALAEONTOLOGY 



Later authors have raised these sub genera to the rank 

 of genera, so that the same species now stand as 



Dalmanella elegant ula (Dalman) ; 

 Schizophoria resupinata (Martin) ; 

 Orthis callactis Dalman. 



The printing of the author's name with or without 

 parentheses in the different cases should be noted 

 carefully. 



6. A later author may unite several hitherto separate 

 genera into one. This is a much rarer case than the last, 

 as the whole tendency of advancing classification is to 

 increase rather than to diminish the number of divisions 

 of all grades. In this case the application of the law of 

 priority leads to the rule that out of the names of the 

 several genera which are being united the earliest name 

 shall be retained as the name of the united genus. 



The names of categories higher than genera cannot be 

 subject to the same rigid law of priority as generic and 

 specific names. 



For families the rule is that the name of the family 

 is formed by combining the name of the type-genus with 

 the patronymic Latin termination idee. Thus the family 

 of which Olenus is the most typical genus is called 

 Olenidce. If for reasons of priority it is found necessary 

 to change the name of the type-genus, the family name 

 must change with it. Thus if it is decided that the 

 generic name Goldius de Koninck has priority over the 

 usually accepted name Bvonteus Goldfuss, then the family 

 name Bronteidce must also be altered to Goldiidce. 



In the case of sub-families the name is similarly formed 

 by combining the root of the name of the type-genus 

 with the termination -inie. Thus the family Phacopidce, 

 typified by the genus Phacops, is divided into three sub- 

 families, named Dalmanilina, Phacopince, and Pterygo- 

 metopinte, typified by the respective genera Dalmanites, 



