134 
Triassic Echinoderms of Bukony. 
The outer surface (fig. 236) is almost flat along the admedian plane, but convex along 
the external border. Thus it has, like the interpyramidal joint-face, an irregulär 
tvvisted appearance. Length 14' 1 mm., greatest width 4‘4 mm. External margin rather 
broken, apparently rather sharp in its middle region, but thickening slightly above 
and considerably below, where it merges in a flattened area continuous with the 
admedian plane and bending round on to the interpyramidal face. The admedian outer 
plane is smooth, not clearly deflned, but about T4 mm. wide. It slopes gently 
into the fovea magna externa, which is not deeply excavate. The fovea is not 
very narrow below; above it is divided by a slight median convexity into two sulci 
(as in Jeruzsälemhegy b). At the upper end the floor of the fovea merges into the 
admedian plane, and the two are truncated by the slightly sloping boundary of the 
supra-alveolar process. 
The symphysial face is about 0'4 mm. wide, broadening to 0'95 mm. below, 
where it joins the dental slide. Its length is 13'3 mm. or 0’94 of the whole length. 
Internal face (fig. 237): central canal wide, but stops where the symphysial face 
expands. Of the lineae eminentes, that adjoining the canal is the more pronounced. 
The dental slide is markedly concave. The styloid process, though distinct, is 
continued upwards as a ridge in line with the admedian border of the slide, thus 
cutting obliquely across the dental sulcus. The sulcus is bounded by an elevation 
or terrace, running up in the direction of the highest point of the supra-alveolar 
process. 
Obviously these alveoli belong to quite a different species from those represented 
by the other specimens. 
Ves&prem, Giricses Domb. (a & b). 
(Plate IX, figs. 238—240) 
Two distal portions of pyramids, the maxillae being still United. Of these b is 
the more complete, since in a most of the ala of the left maxilla is broken away; 
but a (figs. 238—240) is in other respects better preserved. Muschelkalk, Lower 
stratified Limestone. 
Interpyramidal joint-face (figs. 238—240) rather narrow, 5'5 mm. high; L8 mm. 
or more wide. Aboral margin slopes very slightly inwards and downwards. Trans- 
verse ridges have a general direction parallel to the margin, with a faint S curve, 
directed downwards externally and upwards internally. They are 8 or 9 to 1 mm. 
The fossa arcualis is not very distinct, and the supra-alveolar process not well 
preserved. 
The outer surface (fig. 239) is very slightly convex. Length 6’2 mm.; but this is 
not complete. Greatest width (of hemi-pyramid) 1*6 mm. External margin thick. Ad¬ 
median outer plane smooth, about 0'4 mm. wide; but it rounds gently into the 
fovea externa magna, which seems to taper oft' to a point below. 
Symphysial face not seen, probably extends almost the full length of the 
pyramid. 
Internal face not seen. The inner aspect is shown in fig. 240. 
