LOWER HELDERBERG ROCKS. 
365 
lateral furrow passes inwardly from the anterior margin to the narrower 
part of the median lobe, whence, for a short distance, it is nearly 
parallel to the axis, and then diverges abruptly towards the occipital 
furrow. The median furrow is essentially parallel to the anterior lateral 
one; leaving the anterior lateral lobe with parallel sides, a moderately 
arched outline, and having a length about three times as great as the 
width. The occipital furrow is a well-defined semicircular groove, 
showing a transversely oblong slightly elevated tubercle just behind 
the posterior lateral lobe. The occipital annulation is twice as broad 
as the furrow, and moderately convex. The entire head is covered by 
small rounded pustules of unequal size. 
A separate hypostoma, found in the same strata and presumed to belong 
to this species, has a width about one-fourth greater than the length; 
the central portion very broadly ovate, and its margin deeply indented 
below the middle by two oblique sharply impressed furrows, the ante¬ 
rior portion being transversely oval. The lateral borders are broad, and 
the buccal border deeply notched. The surface of the anterior portion 
is finely pustulose. 
A fragment of a pygidium, found in the same beds, preserves one side 
with a portion of the axis. The axis, in its upper part, is abruptly 
elevated, but its comparative height cannot be determined. The ribs 
are broad, and distinctly grooved longitudinally a little in advance of 
the centre. As far as can be ascertained, the axis is contracted a little 
in advance of the middle of its length and expands again below, the 
extremity being probably bifurcate. The surface is pustulose, a single 
row of larger pustules marking centrally each lobe of the ribs. 
Fig. 1. Profile view of an imperfect head. The median lobe of the glabella is not represented 
as sufficiently prominent. 
Fig. 2. View of the upper side. 
Fig. 3. Anterior view, showing the elevation of the median lobe and the frontal limb. The 
surface is represented as too coarsely pustulose. 
Fig. 4. Yiew of the upper side of the head. The median lobe of the glabella is not sufficient¬ 
ly narrowed in its posterior part. The surface markings in this figure present the 
prevailing feature. 
Fig. 5. The median and anterior lateral lobes of the glabella of a larger specimen, which is 
somewhat depressed. 
