GRAPTOLITES. 103 
GRAPTOLITHUS FLEXILIS, Hall. 
Plate X, figures 3-9. 
(G. rurxinis, Hall: Geological Survey of Canada, Report for 1857, page 119.) 
Description.—Frond multibrachiate, composed of numerous slender 
branching stipes, which are bilaterally disposed on the two sides of their 
origin. Radicle minute: funicle short, being little more than one tenth of 
an inch in length, dividing at the two extremities, the parts diverging at an 
angle of about 105°; each one of these again divides within the space of 
a tenth of an inch, making eight principal stipes, which are again several 
times bifurcated. Cellules commencing above the third bifurcation, perhaps 
above the second. Stipes slender flexuous, the branches diverging at a lesser 
angle at each successive bifurcation: stipes and branches filiform at base, 
and measuring in their full width, where the cellules are distinct, from 
four to seven hundredths of an inch, (a very small proportion of the width 
being occupied by the common body) ; curving from the base, and slightly 
arcuate in their entire length. ‘The cellules are usually on the inner side 
of the curve. In the entire length from the first division of the funicle, 
four bifurcations may be counted, and these branches again divide. The 
subdivisions give about sixty-four branchlets in the entire frond, subject to 
some variation from the inconstancy of the subdivisions. 
Cellules short straight narrow, inclined to the axis at an angle of about 
30°; nearly one half the length of each cellule being free: length of 
cellules equal to about four times their diameter; the denticles acute, or 
acutely rounded, varyimg in the same stipe from about twenty-six to 
twenty-eight in the space of an inch ; apertures making an angle with the 
axis of about 90° ; cell-partitions obscurely marked, and traceable nearly 
to the back of the stipe. At the base of the branches the cellules are less 
developed, and sometimes appear as simple undulations of the margin. 
This species is very distinctive in its features, both as to mode of growth 
and manner of bifurcation, as well as in the form and character of cell-denti- 
cles. In the first subdivision of the funicle and stipes, it might be mis- 
taken on cursory examination for G. Logani; but the divergence of the 
first division is always less, and the second subdivisions always diverge at 
a different angle, while the branching of the stipes forms a very distinctive 
feature. The specimens examined show no evidence of ever having 
possessed a central disc. The substance of the stipe has an appearance of 
being more flexible than in any other species, though this character may 
be varied with the condition of preservation or the nature of the imbedding 
material. Under a lens, the axis and principal branches are rounded, with 
_a thin corneous expansion or alation on each side, representing 1 in a figeaee 
the central corneous cup or disc of other species. 
