On the Classification of Mammalia. 



169 



IDEAL GRADATION OF THE CLASS OF MAMMALIA. 



The trunk of Edentata sends out three diverging stems, 

 the Monotremata, the Edentata proper, and the Tardi- 

 grada :* an herbivorous stem (Tardigrada s. Gravigrada), 



* The graphic representation on a plane surface has caused the stem of Tar- 

 digrada to be separated from its trunk ; but in bringing into contact both 

 edges of the plate, we would obtain a figure similar to that of Marsupialia. 

 Instead of a flattened surface, we want an ideal cone for both trunks. 



