329 
[Foerste. 
ing a true Ptilodictya. Examined in the same way low elevations 
or knobs are noticed, which apparently have no great structural 
value. The cells have oval apertures. There are six rows of 
cells on each half of the frond, or twelve rows completing the 
entire circuit. About three and three-fifths cells occupy a length 
of 2 mm. The great thickness of the frond compared with its 
width will readily distinguish this form from any other known. 
Ptilodictya famelicus, sp. nov. 
(PLATE VI, FIG. 32.) 
This species apparently occurs in considerable numbers at 
Eaton, Ohio, considering the number of specimens submitted to 
me by Mr. J. M. Nickles. The fronds are dichotomousty branched, 
the branches not occurring as a rule at less intervals than 4 or 5 
mm. They also vary somewhat in breadth, from 2 mm. to 3 mm., 
the average is about 2.5 mm. In thickness the fronds vary be- 
tween .75 mm. and 1 mm. There are about seven or ten longitudi- 
nal rows of cells on each branch, according to size, and the edge 
of the frond is non-celluliferous for almost, if not quite, a width 
equal to the width of a row of cells. In addition, the cells are also 
arranged in diagonally-crossing rows on the stem. In form the 
cells are oblong oval at their apertures. About five cells occur 
in a length of 2 mm., sometimes almost five and one-half cells. 
The number of longitudinal rows of cells in 2 mm. of width is usu- 
ally about seven, sometimes nearer eight. The surface is perfectly 
normal, having neither elevations nor suppressions of cells. This 
species also occurs in the cementing material of the Clinton con- 
glomerate at Belfast, Highland County, Ohio. 
Ptilodictya rudis, sp. nov. 
(PLATE VI, FIG. 33.) 
This species occurs in considerable numbers at Eaton, Ohio, 
judging from the number of specimens submitted to me by Mr. J. 
M. Nickles. The fronds are dichotomously branched, the branches 
apparently at greater intervals than 5 mm. The fronds vary in 
breadth from 2.3 to 3.5 mm. ; in thickness, from 1 mm. to 1.3 mm. ; 
in the number of longitudinal rows of cells, from six to eight ac- 
cording to the width of the branches. In a length of 2 mm. the 
number of cells varies from four in the far greater number of cases 
to three and one-half in a few instances. In a width of 2 mm. the 
