HIS ZOOLOGICAL RELATIONS. 39 



lar or Protozoan forms, another to the rayed or Eadiate 

 forms, a third to the jointed or Articulate forms, a 

 fourth to the soft-bodied or MoUuscan forms, and a 

 fifth to the backboned or Vertebrate. Whether these 

 subdivisions are of equal zoological value we will not 

 stop to inquire. It is enough for our .present purpose 

 to know that they form portions of the same biological 

 scheme, and are bound together in plan by certain 

 structural characteristics as well as by certain func- 

 tional performances : by structural plan in the posses- 

 sion of corresponding organic parts, and by functional 

 duty in the work of assimilation, growth, reproduction, 

 and other processes peculiar to vitality. As man be- 

 longs to the highest, or Vertebrate section, it is with this 

 that we have more especially to do ; though we must 

 not lose sight of the fact that section is connected 

 with section by affinities which become closer and 

 closer as we ascend from the lower to the higher and 

 more specially organised, and that all reaUy and truly 

 belong to one great but multiform plan. Zoologically, 

 indeed, it would not be difficult — were this the proper 

 place — to show that the Eadiate is but a permanent 

 development of the temporary functional form of the 

 Globular ; the Articulate of the Eadiate ; the Mol- 

 luscan a more concentrated expression of all three ; 

 and the Vertebrate a higher speciaUsation of the Mol- 

 luscan ; while each section is linked to the other by 



