i8 The Science of Life. 



eludes one class or several; and Lankester introduced 

 (1877) the terms " grade" and " sub-grade" for even 

 larger divisions; thus: 



Sub-grade Ccelomata (with body 



Grade B. Metazoa (multicellular) 



Grade A. Protozoa (unicellular) 



cavity). 

 Sub -grade Coelentera (without 



body cavity). 



Sub-grade Corticata (with cortex). 

 Sub-grade Gymnomyxa (naked). 



According to Linnaeus, the individuals composing a 

 species were all descended from an originally created 

 conception pair, whose characters had persisted and 

 of Species. would continue to persist as they were at the 

 first. The number of species might diminish in the 

 course of nature, but it could not increase apart from 

 creation. "There are as many species", he said, "as 

 issued in pairs from the Creator's hands." "There are 

 just so many species as in the beginning the Infinite 

 Being created." Apart from the outcrop of evolutionist 

 views, which were but little heeded, this view of species 

 remained dominant until 1859, when it found its most 

 elaborate expression in L. Agassiz's Essay on Classifi- 

 cation, and its death-blow in Darwin's Origin of Species. 

 While workers like Cuvier had given quite objective 

 definitions, "A species is an assemblage of individuals 

 born by the same parents and of those which resemble 

 these as much as they resemble one another", Agassiz 

 regarded each species as the expression of a divine idea, 

 fixed and eternal. " A species", he said when once 

 asked, " a species is a thought of the Creator." So 

 engrained are evolutionary ideas in the mind of the 

 modern student that he finds it difficult even to under- 

 stand the famous essay of Agassiz, especially when the 

 author proceeds to regard even genera, orders, and 

 classes as created. " This climax", Prof. Ray Lankester 

 notes, "was reached at the very moment when Darwin 

 was publishing the Origin of Species, by which universal 

 opinion has been brought to the position that species, 

 as well as genera, orders, and classes, are the subjective 

 expressions of a vast ramifying pedigree in which the 

 only objective existences are individuals, the apparent 





