24 INTRODUCTION. 



Genitives in u, a single one being more correct. (See Messrs. 

 Allen and Greenough's " Latin Grammar," Part 1, 10, 4, b.) 

 NOTE. Many still existing scientific names are unworthy 

 of retention, but they have not been altered in this volume on 

 account of the established rule of priority, which necessitates, 

 however, many incongruities. The authorities for these names 

 are given in the second index. Great care has been bestowed 

 upon the orthography of English names, since great latitude 

 exists in this respect, no system being yet established. Certain 

 rules have here been followed, with the exceptions produced by 

 general or the best usage. 



