100 CANADIAN FOSSILS. 
21. Graprotitaus Loeant, Hall. 
Plate IX, figures 1-9; and Plate XI, figure 7. 
(G. Logant: Geological Survey of Canada, Report for 1857, page 115.) 
Description.—Frond composed of numerous slender simple stipes, sub- 
equally disposed on the two sides of their origin, or of the minute point mdica- 
ting the radicle. All these, in their perfect condition, have their bases 
embraced within a broad disc. Radicle sometimes well marked: funicle 
short, simple for about three sixteenths of an inch, when it is divided at each 
extremity, the divisions diverging at an angle of 150° or more. Each division 
is again subdivided with more or less regularity, and always near the base, 
until there are from eighteen to twenty-five simple stipes radiating from the 
central disc. ‘There are rarely more than three bifurcations after the first 
division of the funicle, and these all take place within the limits of the 
disc. No cellules are visible on the stipes below the last bifurcation, 
though they do occur within the limits of the disc. On the inner or 
celluliferous side of the disc, the divisions of the funicle, and the bases of 
the stipes beyond, are grooved along the centre. The disc is from one to 
nearly two inches in diameter in different individuals, and with sides cor- 
responding to the number of stipes, between which the margin is concave. 
The substance of the disc is corneous like that of the stipes, extremely 
thin, though composed of double walls; somewhat thickened near the 
centre, and forming only a thin translucent pellicle towards the margin. 
The surface is usually and perhaps always smooth in the centre; while 
towards the margin, and parallel with it, are fine strize of growth. 
The transverse diameter of the stipes, within the limits of the dise, is 
from two hundredths of an inch at the base to four hundredths of an inch 
at its outer margin. The vertical diameter, including the cell-denticles, is 
six hundredths of an inch. The stipe is thickened on the back, and about 
one fifth the width is occupied by the common body. The full width of 
the stipe is attained at about two inches from its origin. Some of the 
stipes have been traced for seven and a half inches from the centre of the 
disc, and their extremities are still imperfect. The cellules are short narrow 
and straight, making an angle with the axis of about 35°, and free for about 
two fifths of theirlength, which is less than three times the diameter of the 
aperture. The margin of the aperture makes an angle of from 90° to 95° 
with the axis: denticles acute, from twenty-two to twenty-six in the space 
of an inch; the prevailing number being twenty-four. Partition-walls 
thin, and obscurely marked on the surface of the stipe. 
This species, when the form is entire, is readily recognized by its numer- 
ous simple elongated stipes. The separated central portions, whether 
