492 PALEONTOLOGY OF ILLINOIS. 



Stictopora crescens, invertis, linearis, ovatipora, perarcta, rigida, 

 semistriata, and vermicula, from the Upper Helderberg group; 

 and crenulata, incisurata, limata, ovata, i-ecta-linea, sinuosa, 

 subrigida, trilineata, and tumulosa, from the Hamilton group. 

 Regarding these Devonian species, I have to say at present only 

 that in my opinion Prof. Hall has drawn the specific lines un- 

 justifiably close, and that in some cases at any rate, he has 

 proposed two names where one would have sufficed. Of other 

 Devonian species, having the structure of fystodictya, S. gilberti 

 Meek, S. meeki Nicholson, and S. sukata Winchell should be 

 mentioned. In the Kinderhook and Burlington beds wo 

 meet with a small undescribed species having pustulose aper- 

 tures arranged longitudinally between low and broad ridges. 

 In the Keokuk limestone C. lineata Ulr., is common, while C. 

 pustulosa, C. americana, and C. nitida, three new species, are 

 more rare. C. ocellata is from a bed in Kentucky, doubtfully 

 referred to the Keokuk group. In the St. Louis limestone we 

 find in great abundance a variety of C. lineata, which might 

 be known as sancti-ludovici; also a wide form that I will pro- 

 visionally designate as var. major. In the Chester group the 

 genus is represented by one or two undescribed species, and in 

 the Coal Measures we find C. carbonaria Meek. The Waverly 

 deposits of Ohio also furnish several species. 



whichever of these five species S. (?) acuta being unavailable), we may select for the type 

 of the genus, we never approach the ground occupied by Cystodictya. Stictopora as 

 now employed by me is based upon S. fenestrata. This species is congeneric with the 

 forms which I formerly proposed to call Rhinldictya, and is one of a number of dis- 

 tinctively Lower Silurian Bryozoa, differing from Eurydictya of the present work 

 almost solely in the form of the zoarium, which, insiead of broad indefinite expansions, 

 forms slender, parallel- sided bifurcating stipes. The student will do well to compare 

 figures on plate XXX with those of CYSTODICTYONID.S; on plates 76, 77 and 78. The 8. 

 fenestrata seems to me to be the most available of the six species originally referred 

 to the genus to stand as the type. S. glomerata, 8. ramosa and 8. labyrinthica are 

 too indefinite to have furnished the generic characters, while S.(?) acuta, although the 

 first to follow the generic description, cannot be utilized because Hall questioned his 

 reference of the species to the genus. 8. elegantula is the only other species having 

 any claim to the distinction. This species is one of a small but little understood group 

 of species, related to Sticlotrypa of this work, that most probably should be regarded 

 as generically distinct from the widely distributed group typified by /S. fenestruta and S. 

 nicholsoni, Ulr. In case 8. elegantula is made the type of the genus, then Bhinidiotya 

 will stand and Stictopora have only two or possibly three representatives. In no case, 

 however, can Stictopora be made to include Cystodictya. 



