W. A. Paries — Parasite from the Devonian Rocks. 137 



the elements of adjacent pillars, two of the sides of the result- 

 ing hexagon are much shorter than the others. A little higher 

 in the skeleton these sides practically disappear, giving in con- 

 sequence rhomboidal openings in the reticulation. A tangen- 

 tial section of this form is seen in fig. 4, while in fig. 5 is seen a 

 diagrammatic representation of the manner in which the rhom- 



vw 



WW 

 WW 



boidal meshes originate. In this diagram the center of the pil- 

 lar is represented by a small cross which will be seen not to 

 conform to the nodes of the reticulation. 



In either species it will be observed that the want of sym- 

 metry in all directions around the pillars will render vertical 

 sections extremely variable and difficult of interpretation. It 

 is further apparent that vertical sections will cut the reticulated 



