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Cincinnati Society of Natural History. 



Formation and locality: Lower Carboniferous shales, at King's 

 Mountain, on the Cin. South. R. R. The strata are probably part of 

 the Keokuk Group. 



CYSTODICTYONID.E, n. fam. 



Zoaria consisting of two or more leaves or layers of cells, grown 

 together back to back by the junction of their basal membranes 

 Zocecia tubular, with a small crescentic lip on one side of the aper- 

 ture, the ends of which project into the visceral cavity of the tubes, 

 and gradually form vertical ridges. Interstitial spaces occupied by 

 vesicular tissue, which, in the matured stage, is almost obliterated by 

 a secondary deposit of sclerenchyma, apparently perforated by minute, 

 vertical, communicating canals. Margins of zoaria sharp or rounded, 

 non-poriferous. 



Type: Cystodictya, Ulrich. 



After a careful study of the genera possessing the above characters, 

 I come to the conclusion that I am not only justified in founding a 

 new family for their reception, but I am obliged to do so. As now 

 known, the family will include Cystodictya, Ulrich, Coscinium, Key- 

 serling, Glyptopora, n. gen. (Coscinium, Prout, not Keyserling), 

 Prismopora, Hall, and Evactinopora, Meek and Worthen. Beside 

 these Rhinopora, Hall, Tainiopora, Nicholson, and Scalaripora, Hall, 

 will, most probably, also be found to belong here, but until their internal 

 structure has been more carefully studied, their systematic position 

 must remain doubtful. In my scheme of classification I placed Cys- 

 todictya in the fam. Stictoporidoi. This disposition of the genus I 

 now regard as erroneous, and much more extended researches, now 

 being carried on, tend to show that the limits of that family, as origi- 

 nally defined by me, are not positive in every case. If my investiga- 

 tions have sufficiently progressed, I propose to revise the Stictoporidoi, 

 and perhaps ^ther families, in the next number, when it is also ex 

 pected that this memoir will be brought to a close. In the meantime 

 it is certain that the characters of Cystodictya, if we lay the greater 

 stress upon cell structure, relate the genus more closely with the Fis- 

 tuliporidoe. than witli the typical Stictoporidoi. In forming my 

 scheme of classification, I at first sought, as much as possible, to 

 found my divisions throughout upon certain characters. Although 

 this desire was not carried out, it nevertheless, I might say uncon- 

 sciously, had an effect upon the result, and the erroneous references 



