198 
Tetragraptus acclinans sp. nO'V. (Plate XXXIII., Fig. 2a-c). 
Tetragraptus approximatus, T. S. Hall, Reports on Graptolites. 
Reo. Geol. Sur., Vic., vol. III., pt. 2, p. 188. 
Tetragraptiis approximatus. Ibid. p. 195 (viz., 4012, 3989, 3999 
4039). 
A recumbent form of Tetragraptus with sufficient characteristics to 
merit specific rank, and likely to be of some value in subzoning the 
Bendigo and Lancefield zones, is T. acclinans sp. nov. This type speci¬ 
men was collected by E. O. Teale. 
Description .—Portion of the sicula 
visible is about 1 mm. long, but owing 
to the method of compression this dimen¬ 
sion is no criterion as to actual length. 
The first and second thecse apparently 
originate near the apex of the sicula, and 
develop in opposite directions, forming 
two stipes of the first order about 3 mm! 
long. About 1 mm. wide near their 
origin, the stipes of the second order 
gradually widen distally to 2 mm. or 
more, and gently curve for about 12 mm., 
when they become rigid and are normally 
disposed at an angle of 90® to the stipes 
of the first order. The longest stipes 
observed measured 40 mm. Thecae eight 
or nine in 10 mm., mucronate, about four 
times as long as wide in contact for about 
half their length, normally inclined at an 
angle of about 40®, but, according to the 
mode of preservation, varying from be¬ 
tween 35® and 52®. Apertural margin 
concave at an angle of 90® to the axis of 
the stipe; ventral margin slightly concave. 
Remarks .—The proximal thecae of the stipes of the second order are 
rarely seen owing, no doubt, to the original position of the stipes and 
the downward direction of the thecae. On compression, these stipes are 
twisted either to one side or the other, a fact attested by neighbouring 
and parallel stipes in some specimens (Plate XXXIII., Eig. 2a) being 
preserved with their thecal apertures facing in the one direction. In 
other specimens (Fig. 63) the ventral margin of the proximal thecae 
become at first indistinctly visible, and are disposed at an abnormal 
angle to the axis of the stipe, but further away, display a tendency 
to assume normality, showing that the proximal thecae are embedded, 
but through twisting of the stipe the distal ones lie on their lateral 
walls. 
Due both to the form of the polypary (particularly to the position 
of the sicula and the widening of the main stipes and the mode of 
compression) the main stipes on the sicula side of the stipes of the first 
order ultimately assume a parallel position at an angle of approximately 
90®, while those on the opposite side are divergent and disposed at an 
angle above 100®. There seems to be little doubt that 90® is about the 
normal position of the main stipes. 
Fig. 63.—Tetragraptus accli¬ 
nans SP. NOV. 
Showing general aspect of polypary of 
young specimen; reverse view' 'xSj 
Lightning Hill anticline, east of Great 
Extended Hustlers Mine, Bendigo, 
collected hy E. O. Teale, Geo. Sur. 
Coll. No. 2763. 
