OF DENISON UNIVERSITY. 
75 
longitudinally between the cell rows. Cells, five in a length of 2 mm, 
seven to eight rows in the same distance in width. 
Meek especially mentions the absence of striations, but the spe- 
cies is very common at the locality he mentions, “Newark, Ohio, 
Coal-measures,” namely, Bald Hill, and well preserved specimens, es- 
pecially clear impressions, readily show the faint undulating stri^ other- 
wise overlooked. 
C. lineata, Ulrich, has a marked longitudinal arrangement of cells, 
with marked longitudinal ridges extending between the cell rows. 
The cells are also fewer in number. 
C. occellata,. Ulrich, has the diagonal series of cells more curved 
laterally and the separating furrows more marked, forming a distinct 
feature of specific value. The branches are also wider. 
Common at Bald Hill. 
Genus, PRISMOPORA, Hall. 
Fronds composed of three cell layers, hence triangular, dividing 
(“ dichotomously,” Ulrich, and) trichotomously ; sides frequently une- 
qual, concave, margin often serrated. Cells in oblique intersecting 
rows, approaching the margins in the serrations, distant from the same 
along the indented area. Interstitial cells in the form of vesicular 
tissue, not visible at the surface. 
V. Prismopora sereata. Meek. 
{Plate VIT, Fig. 6, a, b, c.) 
Ptilodictya (Stictopora) sereata, Meek, 1875, Ohio, Pal. Vol. II, p. 327. 
Cf. Ptilodictya triangulata, 1878, White, Proc. Acad. Nat. Sci. Phil. p. 35. 
Ptilodictya triangulata, 1879, White, Pal. Papers, No. XI, p. 214. 
Ptilodictya triangulata, 1881, White, Appendix, Rep. of looth Meridian, 
p. XXIV. 
Ptilodictya triangulata, 1883, White, Contrib. to Invert. Pal. p. 13 1. 
Prismopora serrulata, 1884, Ulrich, Am. Pal. Bryozoa, p. 41. 
Zoarium dividing ; dichotomous branching alone observed, but 
since the specimens are mostly in casts and never free, it can not be 
determined with certainty that there was not a third branch. Speci- 
mens from Danville, Illinois, found free, are all trichotomously di- 
vided as far as we have observed. Branches triangular; the sides 
sometimes very irregular. The sides are concave, concavity variable, 
although always distinct. The three edges are all sharp and serrated 
