1 88 1.] TJie Paleontologist. 39 



rows between straight, parallel, elevated lines. At the base, to a height 

 of a little over a line, there are only a few, much elongated pores, and 

 no elevated lines, giving to that part of the frond a sub-solid appearance; 

 above that, to a distance of one line more, there are from six to eight 

 rows of cells, and higher on the frond they are increased to about ten 

 rows, the additional rows commencing at the margins as the frond ex- 

 pands. The cells are oval or sub-circular, and the mouths slightly raised, 

 6 or 7 occupying the space of one line, measuring in a longitudinal di- 

 rection. Length of the specimens used for this description, 5 ^4 lines, 

 width a little over one line at the broadest part. 



This species differs from Ptilodictya flagcllum, Nicholson (Pal. Ohio, 

 vol. ii., p. 262, pi. 25, fig. 4), in being straight instead oi falciform, and 

 the base not " bent from side to side in afexuous manner,'' as that species 

 is described and figured. 



Locality : Clinton county, Ohio, in the upper beds of the Cincinnati 

 Group, Lower Silurian Formation. 



Ptilodictya (?) cincinnatienses, sp. nov. James. 



Polyzoary, the parts examined, consisting of sub-cylindrical, or cylin- 

 drical stems, giving off lateral branches from half a line to one line 

 apart, at an angle, generally, of about 45 degrees; branches varying in 

 length from half a line to over one line ; diameter of stems about 

 half a line. The pores vary from long oval to sub-circular in shape, and 

 are arranged in alternating rows, three or four in the space of half a line 

 measuring their longer diameter (longitudinally), and nearly twice that 

 number transversely ; separated, generally, about their own diameter 

 apart : margins of cell mouths not raised on any of the specimens exam- 

 ined : only a single, depressed, sinuous line between the pores in most 

 cases, but occasionally there are two causing one elevated line and giv- 

 ing to such examples the appearance of a striated surface. The speci- 

 mens used for this description are from two to three lines in length, and 

 have ^jointed appearance at the lower end in all cases, and sometimes 

 at the upper. 



The surface markings of some specimens of this species resemble, 

 somewhat, Ptilodictya cleavclandi, but the stems are generally nearly 

 cylindrical, whilst of that species they are always flattened, and the pores 

 of this are more elongated and more widely separated. Some examples 

 are more or less flattened by pressure, apparently. 



Found on the Cincinnati hills, between 200 and 350 feet above low 

 water mark of the Ohio river, and at other localities in the Cincinnati 

 Group, at about the same horizon. 



Ptilodictya grahami, sp. nov. James. 



Polyzoary commencing at a rather bluntly-pointed base, slightly 

 curved to one side, gradually expanding to a height of about one line, 

 where a very short, spur-like branch is given off; about half a line higher 

 it branches dichotomously at an angle of about 45 degrees, and half a 



