466 PALAEONTOLOGY OF ILLINOIS. 



CERAMOPORELLA GRANULOSA Ulrich. 



PI. XLI, flg. 2, 2a. 



Zoarium forming masses, consisting of many superimposed 

 layers, the initial layer being attached to some foreign body; 

 in the type specimen a species of Pachydictya. Surface even, 

 granulose with groups of larger cells. Zooecia oval, direct to 

 the surface. Lunarium prominent, narrow, occupying from one- 

 fourth to one-third the circumference of the wall. Apertures 

 somewhat oblique, irregularly oval, from 0.2 to 0.3 mm. in 

 diameter, in diagonally intersecting series, about six in two 

 mm. A considerable number of rather small irregular mesopores 

 are scattered about among the zooecia. Rather abundant thin 

 diaphragms intersect the tubes. A large number of small dark 

 spots, precisely like acanthopores in tangential sections occur 

 in the walls. Vertical sections, however, show that unlike these 

 structures they do not form continuous thick-walled tubuli, but 

 that they are developed at successive levels corresponding with 

 the diaphragms. 



The granules, numerous diaphragms, and less regular arrange- 

 ment of its parts, distinguish this species from C. distincta 

 which it resembles in the size of the zooecia. I am not acquainted 

 with any other species that would admit of closer comparisons. 



Position and locality: Cincinnati group; Wilmington, 111. 



CERAMOPORELLA? OHIOENSIS Nicholson. 



PI. XXXIX, flg. 2. 2a. 

 Ceramopora ohloensis Nich. 1875. Pal. Ohio, Vol. II, p. 265. PI. XXV, flg. 10,10e. 



Zoarium incrusting, forming thin expansion over other Bryo- 

 zoa or the shells of Brachiopoda, 0.5 to 1.5 mm. thick, com- 

 posed, usually, of but a single layer, but sometimes of two or 

 three superposed layers. Surface with slightly elevated clusters 

 of zooecia of larger size and with thicker walls than usual. Zo- 

 cecia at first prostrate then rising abruptly, proceed almost 

 direct to the surface. Walls moderately thick. Apertures vary- 

 ing in shape, but more or less triangular or snbromboidal, and 

 oblique on account of the prominent elevation of the overarch- 

 ing lunarium or hood. Zooecia arranged in obscure radiating 



