354 T ' HE BIOCOSMOS PARTICULARIZED. 



there is a good deal of doubt about their posi- 

 sition in the line, the systematists ranking 

 them diversely. Examples are the oyster, 

 snail, cuttle-fish. The vegetal form has dis- 

 appeared, and a distinct bi-lateralism has 

 arisen; but the Mollusks are not yet seg- 

 mented into successive rings, like the worm 

 (see next division). The skeletal arrange- 

 ment is variable: sometimes inside (cephalo- 

 pods), sometimes outside (bivalves and uni- 

 valves), sometimes quite non-existent. It 

 would seem that in the mollusks the skeleton 

 is in its uncertain stage, but on its way to its 

 articulated form which culminates in the ver- 

 tebral animal. 



C. THE SEGMENTATES, beginning with the 

 worms and reaching to man who is included. 

 This division is based upon the so-called seg- 

 mentation of the animal organism, its skele- 

 tal arrangement being a series of concentric 

 rings of more or less rigid material. The In- 

 vertebrates of this sort Cuvier called Articu- 

 lates .though he excluded the well-articulated 

 vertebral column of the higher animals ; pos- 

 sibly he could not think of man's skeleton 

 with that of a worm or insect. Such articu- 

 lation we may conceive as a return to the 

 Plant-animals (Phytoids or Anthozoa), and 

 as an association of a number of them into a 

 new organism, which still shows their original 



