BRYOZOA. 509 



EVACTINOPORA RADiATA Meek and Worthen. 



PI. LXXm, flg. 3, 3a. 



Eractinopora radiata M. & "W. 1865. Proc. Acad. Nat. Sci. Phila, p. 165. 

 Evact inopora radiata M. & W. 1868. Geol. Surv. Ill voL 3, p. 502, PL XVII, flg. 2o, 2&. 

 Eractinopora radiata Ulrich, 1884. Jour. Cin. Soc. Nat Hist. voL 7, p. 42, PI. H, flg. l-le. 



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 carcareous ma- 

 terial, so that the "body" of the star, as seen in a basal view, 

 is comparatively strong and the rays correspondingly short 

 and blunt. The edges of the rays are preserved in the regularly 

 rounded base as angular converging ridges, separated by at 

 first very shallow, then gradually deepening and widening fur- 

 rows. At a point about midway between the summit and base 

 where the rays become free, they are acutely elliptical in trans- 

 verse section, four or five mm. in width, with a non-poriferous 

 border on each edge, the outer one a little the widest; from 

 this point the margins are parallel for a short distance, then 

 converging slowly, till they meet at the narrowly rounded ex- 

 tremity. The whole base for nearly one-third the distance up 

 the side of the rays, is non-poriferous at the surface, the zooe- 

 cia apertures here being covered by a granulo-striate deposit of 

 sclerenchyma, decreasing in thickness upward. Zooecia prostrate 

 at first, then arising from the mesial laminae, proceed to each 

 surface of the rays at an angle of about 45. Apertures sub- 

 circular, oblique, the lower margin being most elevated; about 

 Q.2'2 mm. in diameter, the same distance or less apart, arranged 

 in not very regular intersecting series, with eight or nine in 

 three mm. Interspaces occupied by small lenticular vesicles, a 

 few of which remain open, especially on each side of the mesial 

 plane, the rest being filled and obscured by vertically perforated 

 dense tissue, the perforations appearing in tangential sections 

 as exceedingly numerous minute dark spots. Scattered among 

 them are other spots of large size, that resemble acanthopores, 

 in having the central portion lucid. Lunarium inconspicuous. 



Position and locality: Keokuk group. King's Mountain. Ky.. 

 and at an undetermined locality in Missouri (M. & W.). 



