Silurian.] PALZONTOLOGY OF VICTORIA. [ Graptolites. 
All these are Lower Silurian, or Cambrian rocks, I think of the 
age of the Llandeilo flags. 
EXPLANATION OF FicurREs. 
Plate XX.—Fig. 3, large specimen, natural size, with wide angle of divergence and short 
thick radicle. Fig. 3a, portion of cells of ditto magnified. Fig. 4, another specimen with 
smaller angle of divergence, natural size, with smaller radicle. Fig. 4a, portion of cells of ditto 
magnified. Fig. 5, smaller specimen with most acute angle of divergence and very long radicle. 
Fig. 5a, portion of ditto magnified. 
Prate XX., Fia. 6. 
DIPLOGRAPSUS PALMEUS (Barr. sp.). 
[Genus DIPLOGRAPSUS (McCoy). (Sub-kingd. Radiata. Class Zoophyta. Order Hy- 
droida. Fam. Graptolitide.) 
Gen. Char.—Stem simple, straight, with a slender central axis, and two oblique rows of 
cells in one plane, one row on each side of the axis. Tip of axis sometimes developing an 
ovarian vesicle. } 
Derscrrprion.—Elongate, linear, ovato-lanceolate, from 14 to nearly 8 inches in 
length; upper portion linear, with straight sides, gradually tapering to the truncated 
upper end, which is usually about ;1, of an inch wide; the width often slightly increases 
nearer the base, which is then slightly ovate from the rapid tapering to the base. 
The midrib is distinctly continued beyond the upper end, a variable length often 
terminating in a wide cordate or pyriform (? ovarian) vesicle about 4 wider (when 
flattened) than the celluliferous stem, and varying from complete continuity to separa- 
tion by 4 an inch of midrib. Cells narrow, tubular, diverging in straight lines, or 
nearly so, 7 in 2 lines; the outer oblique end slightly concave, simple; the lower 
edge rather more than twice the terminal edge in length; cell tubes forming an angle 
of about 35° with the midrib. 
REFERENCE.— Grapt. palmeus (Barrande), Grap. de Bohéme, t. 8, f. 1 to 7 
(excl. 5 and 6). 
I believe the curious smooth dilatation so frequently found at 
the upper end of this species to be an ovarian vesicle, and I think 
it is probably pear-shaped, because it presents a similar cordiform 
outline whether compressed in the plane of the cells or at right 
angles thereto. It varies in position, sometimes being separated 
from the cells by a length of 3 an inch of naked midrib, and 
sometimes being united at base to the cellular tip by its whole 
width. There can be no doubt of the perfect identity of the 
Australian and Bohemian specimens, on one of which latter (placed 
for comparison in the Melbourne Museum) I have detected the 
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