CHAPTER X. 



POLYZOANS. 

 Phacelopora pertenuis ULRICH. 



Plate xxxiii, fig. 3. 



Phacelopora pertenuis Ulrich, 1890: Geol. Sur. Illinois, vol. VIII, p. 406, 

 pi. xxix, figs. 1-lc. 



Horizon and localities Lower Silurian, Trenton lime- 

 stone : Thebes ( Illinois ).; apparently the same form occurs in 

 Missouri below Cape Girardeau. 



Homotrypa arbuscula ULRICH. 



Homotrypa arbuscula Ulrioh, 1890: Geol. Sur. Illinois, vol. VIII, p. 409, 

 pi. xxxviii, figs. 3-3c. 



Horizon and localities. Lower Silurian, Trenton lime- 

 stone : Calhoun county ( Illinois ). 



Leioclema gracillimum ULRICH. 



Leioclemi gracillimum Ulrich, 1890: Geol. Sur. Illinois, vol. VIII, p. 429, 

 pi. Ixxv, figs. 6-6b. 



Horizon and localities Lower Carboniferous, Burlington 

 limestone: Hannibal; Keokuk limestone: Clark county; 

 Keokuk (Iowa) ; Warsaw ( Illinois ). 



Leioclema punctatum (HALL). 



Callopora punctata Hall, 1858 : Geology Iowa, vol. I, p. 653. 



Callopora missouriensis Rorninger. 1866: Proc. Acad. Nat. Sci., Phila., 



p. 117. 

 Leioclema punctatum Ulrich, 1882: Jour. Cincinnati Soc. Nat. Hist., vol: 



V, p. 141, pi. vi, fig. 1-la. 

 Leioclema punctatum Ulrich, 1890: Geol. Sur. Illinois, vol. VIII, p. 430. 



Zoarium large, dichotomizing; branches three or four mil- 

 limeters in diameter, and arising from broad basal expansions 



