312 ESSAY ON CLASSIFICATION. 



times as many as Linnaeus had done. Again, Linnaeus 

 divides his classes into orders ; next, he introduces genera, 

 and finally, species; and this he does systematically in 

 the same gradation through all classes, so that each of 

 his six classes is subdivided into orders, and these into 

 genera with their species. Of families, as now understood, 

 Linnaeus knows nothing. 



The classification of Cuvier presents no such regularity 

 in its framework. In some classes he proceeds, imme- 

 diately after presenting their characteristics, to the enu- 

 meration of the genera they contain, without grouping 

 them either into orders or families. In other classes, he 

 admits orders under the head of the class, and then pro- 

 ceeds to the characteristics of the genera, while in others 

 again he admits under the class not only orders and fami- 

 lies, placing always the family in a subordinate position 

 to the order, but also a number of secondary divisions, 

 which he calls sections, divisions, tribes, etc., before he 

 reaches the genera and species. With reference to the 

 genera again, we find marked discrepancies in different 

 classes. Sometimes a genus is with him an extensive group 

 of species, widely differing one from the other, and of 

 such genera he speaks as "grands genres;" others are 

 limited in their extent, and contain homogeneous species 

 without farther subdivisions, while others again are sub- 

 divided into what he calls sub-genera, and this is usually 

 the case with his " great genera." 



The gradation of divisions with Cuvier, then, varies 

 with his classes, some classes containing only genera and 

 species, and neither orders nor families nor any other 

 subdivision. Others contain orders, families, and genera, 

 and besides these a variety of subdivisions, of the most 

 diversified extent and significance. This remarkable in- 



