LIFE ON THE EARTH. 211 



way. But postulates in the sense here used are 

 equivalent to special endowments, not in the least 

 easier to conceive of than separate creations; for 

 what are these but endowments, and has not every 

 special structure its appropriate germ and mode of 

 growth? 



If it is not possible in the existing ocean, among 

 the innumerable and variable radiated, amorphozoan, 

 and foraminiferous animals, to construct one chain 

 of easily graduated life, from the fertile cell to the 

 prolific ovarium and digestive stomach, it must be 

 quite in vain to look for such evidence in the fossil 

 state. In the face of the assumptions requisite to 

 imagine such a chain, we cannot venture to adopt 

 it as a probable hypothesis, and thus the idea of 

 one general oceanic germ of life, whether we like 

 it or not, must be abandoned. Reasoning of the 

 same kind will convince us that to derive by any 

 probable steps any one great division of the animal 

 kingdom from another, involves too much of hazard- 

 ous assumption to be adopted by a prudent in- 

 quirer. 



Take therefore the hypothesis in an easier shape, 

 and accept as primary structures in general forms 

 all the great invertebral divisions which reside in 

 water; let us suppose them capable of indefinite 

 variation, and inquire what is the geological evidence 



P2 



