1 62 Cells; or, Evolution. 



time. In short, these gradational shades have long 

 been acknowledged in the well-known circumstance 

 that so many different systems of classification are 

 devised, to describe nature systematically, if that 

 be possible. But the fact is, nature is like a net- 

 work, and nowhere exhibits a line such as evolu- 

 tion demands for its march upwards. 



178. After these general strictures on the value 

 of " transitional " forms, let us take up the particu- 

 _. . ... lar case of the mollusk, called ascidian, 



The Ascidian J ■ 



and the and the very low form of fish, called 



Amphioxus. amphioxus, which have been put for- 

 ward to fill the gap between the lower orders and 

 the vertebrate fishes. For otherwise these latter, 

 to the scandal of evolution, come in at the stage 

 of the upper Silurian, without any transitional 

 form to usher them in. As to the ascidian, Verrill 

 has observed, after a thorough study of this mollus- 

 can tribe, that its alleged relation to the vertebrates 

 is without the slightest foundation in its structure. 

 On the other hand, the vertebrate, amphioxus, be- 

 ing a fish, agrees with the fishes; having no brain, 

 it seems to agree with the mollusks. Hence the 

 argument is implied that, after being originally 

 a brainless mollusk, it made the passage over to 

 the fishes by thinking itself into a vertebral col- 

 umn; and it left the mollusks on one side and 

 got among the fishes on the other. I think we 

 may leave this amphioxus to the tender mercies of 

 Catagenesis or Degeneration (No. 132), which has 



