240 ESSAY ON CLASSIFICATION. 



merits in Zoology have gone to limit genera gradually 

 more and more in such a manner that the species belong- 

 ing to each have shown successively less and less differ- 

 ence in form, until they have assumed, in that respect, 

 the most homogeneous appearance. Are natural genera 

 any more to be distinguished by their form one from the 

 other r ( Is there any appreciable difference in the general 

 form 1 I say purposely general form, because a more or 

 less prominent nose, larger or smaller ears, longer or 

 shorter claws, etc., do not essentially modify the form. 

 Is there any real difference in the general form between 

 the genera of the most natural families'? Do, for instance, 

 the genera of Ursina, the Bears, the Badger, the Wolve- 

 rines, the Raccoons, differ in form I Do the Phocoidse, the 

 Delphinoidre, the Falconinae, the Turdinse, the Fringil- 

 linse, the Picinse, the Scolopacinse, the Chelonioidse, the 

 Geckonina, the Colubrina, the Sparoidse, the Elateridse, 

 the Pyralidoidse, the Echinoidae, etc., differ any more 

 among themselves? Certainly not; though, to some ex- 

 tent, there are differences in the form of the representa- 

 tives of one genus when compared with those of another 

 genus; but, when rightly considered, these differences 

 appear only as modifications of the same type of forms. 

 Just as there are more or less elongated ellipses, so do we 

 find the figure of the Badgers somewhat more contracted 

 than that of either the Bears, or the Raccoons, or the 

 Wolverines, and that of the Wolverines somewhat more 

 elongated than that of the Raccoons; but the form is 

 here as completely typical as it is among the Viverrina, 

 among the Canina, or among the Bradypodidee, or among 

 the Delphinoidso, etc. We must, therefore, exclude form 

 from the characteristics of natural genera, or at least in- 

 troduce it only as a modification of the typical form of 

 natural families. 



