24 POLYZOANS. 



. Fenestella tenax ULRICH. 



Fenestella tenax Ulrich, 1890 : Geol. Sur. Illinois, vol. VIII, p. 546, pi. li, 



figs. 2-2e. 



Horizon and localities Lower Carboniferous, Kaskaskia 

 limestone: Chester (Illinois). 



Fenestella cestriensis ULRICH. 



Fenestella cestriensis Ulrich, 1890 : Geol. Sur. Illinois, vol. VIII, p. li, 

 figs. 5-5b. 



Horizon and localities. Lower Carboniferous, Kaskaskia 

 limestone : Chester ( Illinois ). 



Fenestella flexuosa ULRICH. 



Fenestella fiexuosa Ulrich, 1890: Geol. Sur. Illinois, vol. VIII, p 548, pi. 

 li, figs. 4-4c. 



Horizon and localities. Lower Carboniferous. Kaskaskia 

 limestone : Chester ( Illinois ). 



Fenestella shumardi PROUT. 



Plate xxxiv, figs. 2a-b. 



Fenestella shumardi Prout, 1868: Tr^ns. St. Louis Acad. Sci., vol. I, p. 



232. 

 Fenestella shumardi Meek. 1872 : U. S. Geol. Sur. Nebraska, p. 153, pi. 



vii, figs. 3-ab. 



Polyzoum growing apparently in flabelliform expansions 

 and composing an extremely fine delicate network; branches 

 very slender, of uniform size, rather flattened and compara- 

 tively coarsely striated on the non-poriferous side, bifurcating 

 at rather regular intervals of from 0.20 to 0.25 inch, the divi- 

 sions diverging but slightly ; fenestrules oblong or about once 

 and a half to nearly twice as long as wide, distinctly quadran- 

 gular, especially as seen on the non-poriferous side, and about 

 equaling the breadth of the branches ; dissepiments extremely 

 slender or scarcely more than one-fourth as thick as the 

 branches, not widened at the end on the non-poriferous side, 

 but often somewhat expanded by a pore at one or both ends 

 on the other side. Poriferous side with a mesial carina appar- 

 ently sometimes bearing minute projecting points, and on each 

 side of this angle about two and sometimes three compara- 



