POLYZOA.NS. 19 



Zoarium small, delicate, depressed, composed of six flat- 

 tened expansions, radially placed. Zooecial apertures sub- 

 circular, closely arranged. 



Horizon and localities Lower Carboniferous, Burlington 

 limestone: Louisiana; Burlington ( Iowa). 



Evactinopora grandis M.EKK & WORTHEN. 



Eractinopora grandis Meek & Worthen, 1863: Geol. Sur. IJlinois, vol. Ill, 



p. 503, pi. xv, figs. 2a-b. 

 Ecactinopora grandis Uirich, 1890: Geol. Sur. Illinois, vol. VIII, p. 511, 



pi. Ixxiii, tig. 4. 



A very large, robust form, with four rays arranged at right 

 angles to one another, and measuring from 6 to 10 centimeters 

 from end to end. 



Horizon and localities. Lower Carboniferous, Burlington 

 limestone : Louisiana, Hannibal. 



Evactinopora radiata MEEK & WORTHEN. 



Evactinopora radiata Meek & Worthen, 1865: Proc. Acad. Nat. Sci., 



Phila.,p. 165. 

 Evactinopora radiata Meek & Worthen, 1868: Geol. Sur. Illinois, vol. Ill, 



p. 502, pi. xvii, figs. 2*-b. 

 Evactinopora radiata Ulrich, 1884: Jour. Cincinnati Soc. Nat. Hist., vol. 



VII, p. 42, pi. ii, figs. 1-le. 

 Evactinopora radiata Ulrich, 1890: Geol. Sur. Illinois, vol. VIII, p. 509, 



pi. Ixxiii, figs. 3-3a. 



Zoarium ellipsoidal in outline when complete, consisting 

 of from six to eight bilaminar vertical folia, arranged in a 

 radiate manner. In the basal half of the zoarium the folia or 

 rays are united and much thickened by a deposit of calcareous 

 material, so that the ''body" or the star as seen in the basal 

 view is comparatively strong, and the rays are preserved in 

 the regular rounded base as angular covering ridges, separated 

 by at first very shallow then gradually deepening and widening 

 furrows. At a point about midway between the summit and 

 base where the rays become free, they are actually elliptical in 

 transverse section, four or five mm. in width, with a non-pori- 

 ferous border on each edge the outer one a little the widest : 

 from this point the margins are parellel for a short distance, 

 then converge slowly, till they meet at the narrowly rounded 



