Silurian.} PALZONTOLOGY OF VICTORIA. [ Graptolites. 
square straight-edged interspaces between the cell notches nearly as wide as the 
branches; inner edge of branches thickened and obliquely undulated, with an 
indentation opposite each cell; width of branches, 3 line; about 4 cells in 2 lines. 
ReFERENCE.— Graptolites furcatus (Hall), Pal. N. Y., v. 1, t. 74, f 4. 
This is a rare species in Victoria, but is unmistakably identical 
with the North American examples. 
In the reddish and whitish Llandeilo flags of B* 64. 
EXPLANATION OF FIGURES. 
Plate XX.—Fig. 7, average specimen, natural size. Fig. 7a, portion of branch magnified. 
(The oblique indentations on the left hand or inner edge are rather too strong in the lower part 
of the figure, the indented angle being too acute and entering the substance of the branch too 
far ; the slight obliquity of the cell notches towards the top of the figure is due to compression.) 
e 
Pratt XX., Fia. 9. 
GRAPTOLITES (DIDYMOGRAPSUS) GRACILIS. 
DescriptTion.—Basal non-celluliferous stipe excessively slender (about } of a 
line wide), thread-like, upwards of 2 inches long and gently curved sigmoidally ; 
from this the celluliferous stems arise at regular intervals from one side, the bases 
being about 1 line apart, and as slender as tne basal common tube from which they 
arise, the common canal along the back continuing of this size ; cell-teeth slightly 
obtuse, distant from each other about twice the width of the branch, the upper edge 
of each about 4 the length of the outer oblique side; length of each celluliferous 
an rarely exceeding 1 inch, greatest width about 4 of a line; cell-teeth about 3 
in 1 line. 
REFERENCE.— Graptolites gracilis (Hall), Pal. N. Y., v. 1, t. 74, fig. 6. 
So small and inconspicuous are the cells in this strange species, 
that the common canal running along their back can alone be seen, 
and as this is about the size of the creeping root-like stipe, the 
appearance is so like that of a Rastrites that one would almost 
suspect Mr. Harkness’ Rastrites Barrandi to be of this nature ; a 
slight roughness of the apparent branches, as in our figure, alone 
indicating the place of the cells, and a difference from the true 
Rastrites tubular cells. In a good light, however, the cells may be 
seen in our Australian specimens exactly as in the New York 
examples, with which they are quite identical. Although I have 
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