Lower Silurian.'] PALEONTOLOGY OF VICTORIA. IGraptolitei. 



River, 1 mile from Bacchus Marsh road (B" 71) ; flags of Kangaroo 

 Creek, S. of Kangaroo township (B" 80) ; in slates of W.L.S. 2. 



Explanation of Figukes. 



Plate I. — Fig. 1, elliptical narrow variety, natural size. Fig. 2, slightly ovate form, natural 

 size. Fig. 2a, portion magnified, showing the thick axis and direction of the middle cells ; the 

 cell points are usually rather more slender than in this figure, and tlie mouth of each cell should 

 be slightly more extended along the lower margin outward, so as to be very slightly oblique and 

 concave. Fig. 3, more parallel-sided variety, with equal ends, natural size. Fig. 4, large ovate 

 variety, natural size. 



Plate L, Fig. 5. 

 DIPLOGRAPSUS MUCRONATUS (Hall sp.). 



[Genu? DIPLOGRAPSUS (McCoy). (Sub-kingd. Radiata. Class Zoophyta. Order Hy- 

 droida. Fam. Graptolitidse.) 



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.] 



Description. — Polypidom simple ; about 1^ inches long', and 1 line wide (in 

 slate), tapering rather abruptly towards the base ; denticular cells 5 in the space of 

 2 lines, outer and lower margin oblique, upper margin nearly horizontal, the angle 

 produced into a long, slender, flexible filament; central axis excessively fine hair 

 like. 



Reference. — Graptolites mucronatus (Hall), Pal. N. Y., t. 73, fig. 1. 



A beautiful and distinct species, easily recognised by the little 

 mucronate film terminating each denticle, and which films, fi'om 

 their flexil>ility, extend in every direction, upwards and dowuAvards, 

 or horizontally. Professor Hall describes the S2)ecies from the 

 partially altered slates of the Hudson River group, near the upper 

 limit of the New York Cambrian system (probably not far from 

 the parallel of the liritish Caradoc shale). 



Very abundant and beautifully preserved in the white decom- 

 posed (Llandeilo flags) soft shale (B" 67) of section 24, parish of 

 Bulla. 



Explanation of Figukes. 



Plate I. — Fig. 5, specimen, natural size, with an unusual prolongation of the axis above, 

 without cells. Fig. 5o, portion magnified, 



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