R84 GRADATION AMONG ANIMALS. 
CHAPTER Vz. 
GRADATION AMONG ANIMALS. 
Wuat, then, is the relation of these larger 
groups to each other, if they do not stand in a 
connected series from the lowest to the highest ? 
How far are each of the branches and each of 
the classes superior or inferior one to another? 
All agree, that, while Vertebrates stand at 
the head of the Animal Kingdom, Radiates are 
lowest. There can be no doubt upon this point ; 
for, while the Vertebrate plan, founded upon a 
double symmetry, includes the highest possibili- 
ties of animal organization, there is a certain mo- 
notony of structure in the Radiate plan, in which 
the body is divided into a number of identical 
parts, bearing definite relations to a central verti- 
cal axis But while all admit that Vertebrates 
are highest and Radiates lowest, how do the Ar- 
ticulates and Mollusks stand to these and to each 
other? ‘To me it seems, that, while both are de- 
cidedly superior to the Radiates and inferior to 
the Vertebrates, we cannot predicate absolute 
superiority or inferiority of organization of either 
‘ 
ae e® ee ee a 
