160 PROCEEDINGS OF THE ACADEMY OF 



As seen on the non-poriferoiis side, this species closel}'' re- 

 sembles Prof. McCoy's figure of his F. plebeja, as represented 

 natural size, excepting that it forms a sliglitly finer network. 

 Under a magnifier, however, it is seen to differ in having a row 

 of little nodes along each branch, and I have not seen any longi- 

 tudinal stria on its branches, though they probably exist on those 

 of perfect specimens. The magnified figure of the poriferous 

 side of F. loleheja shows still more important differences, its fenes- 

 trules being proportionally much longer, with four or five pores 

 opposite each side. The little nodes or i^rojections along the 

 middle ridge of this side of the branches in our species do not 

 exist in F. plebeja, nor does the latter usually have a pore oppo- 

 site the end of each dissepiment, as in the species under consider- 

 ation. 



Localitij and position. Lodi, Ohio. Waverley group of Lower 

 Carboniferous. 



PTILODICTYA (STICTOPORA) CARBONARIA, Meek. 



Ramose, branches from their origin generallj'' nearly equalling 

 the breadth of the stem from which they spring more or less al- 

 ternately and at angles of about 50° to 60°; poriferous surfaces 

 of each side flattened convex; lateral margins sharp and smooth; 

 pores arranged in quincunx so as to form about seven to nine 

 longitudinal rows (those of each two adjacent rows alternating), 

 and about the same number of pores may be counted in each ob- 

 lique row, very nearly or quite circular, and each with a promi- 

 nent margin, so as to appear as if penetrating minute pustules ; 

 intervening spaces usually about once and a half to twice the 

 breadth of the pores, and smooth or without longitudinal ridges 

 or furrows. 



Entire size unknown ; breadth of medium-sized branches, 0.14 

 inch; thickness in the middle, 0.05 inch; number of pores in a 

 space of 0.10 inch of each longitudinal row, six; while in the 

 oblique rows about seven may be counted in the same space. 



Among the Silurian species of Stictopora, this seems to agree 

 most nearly with S. pnnctipora, Hall, from the Niagara Group, 

 which it nearly resembles in its round pores with raised margins, 

 as well as in the number and arrangement of its pores. It differs, 

 how^ever, in having its sharp lateral margins smooth, instead of 

 being striated. A critical comparison of specimens from these 



[August 15, 



