530 PALEONTOLOGY OF ILLINOIS. 



number of irregularly arranged minute dark spots, which only 

 in rare and very limited instances arrange themselves in trans- 

 verse lines. 



The mode of growth and cell arrangement as well as the ir- 

 regular disposition of the intra-zooecial dots distinguish T. 

 frondosa from the other species of the genus. 



Position and locality: Keokuk group, Keokuk, Iowa. 



T^ENIODICTYA CINGULATA UMch. 

 PL LXVII, Fig. 3-3b. 



The only specimen examined of this species is a very large, 

 more or less dichotomously branched stipe, three to five mm. 

 wide. The specimen is split through the center, showing one 

 side of the median lamina. Celluliferous face imbedded in the 

 matrix and not seen. The arrangement of the zocecia as shown 

 by thin sections, though similar to that of T. ramulosa, differs 

 in having the diagonal lines straighter and more pronounced; 

 diagonally about eight in two mm., longitudinally six in the 

 same space. The zooecia are elongate-hexagonal, the outlines 

 being formed by a transversely lined interspace. 



In T. ramulosa, this lined interspace does not surround the 

 zooecia, but continues as a flexuous band between the longitudi- 

 nal series of cells. The present species is further distinguished 

 by its wider branches. 



Position and locality: Keokuk group; Warsaw, 111. 



T^NIODICTYA SUB RECTA Ulrich. 

 PI. LXVII, Fig. l-4d. 



Zoarium an erect stipe, branching dichotomously; angles be- 

 tween branches about thirty degrees; width of branches between 

 2 and 3 mm., slightly less immediately after each bifurcation. 

 Cell apertures oval, in from twelve to sixteen longitudinal series, 

 appearing as though ranged between raised ridges, nine at the 

 margins and eleven at the center of the branch in three mm. 

 longitudinally; interspaces thin. 



