Echinoid Jaw-fragments. 131 
Ferussdlemhegy (b). 
(Plate IX, figs. 223—225.) . 
The maxilla of a right hemi-pyramid. Raiblian. 
The inter-pyramidal joint-face (fig. 223) is narrow, being 6°8 mm. long, and 
attaining a width of only 2°8 mm. at 4°3 mm. from the distal end. Its aboral 
margin slopes, if anything, outwards and downwards (not as usual in Cidaridae). 
The transverse ridges, which are almost parallel to it, have a slight S curve, 
directed downwards externally and upwards internally, but their general direction 
is at right angles. to the long axis of the surface. There are 6 to the millimetre. 
The fossa arcualis is narrow, 0°8 mm. at base of supra-alveolar process, which 
is 2°5 mm. high. = 
The outer surface (fig. 224) is also narrow and with only a very slight con- 
vexity. Length, 90 mm.; greatest width, just below the foveola arcualis, 26 mm. 
The external margin is sharp, thickening below. The admedian outer plane is smooth 
and 0'9 mm. wide. Between these two lies the fovea magna externa, narrow and 
rather deeply indented below, but broadening out above and becoming divided by 
a very slight median convexity into two sulci, of which one lies alongside the margo 
externus proeminens, ending in the foveola arcualis, while the other dies away as 
the floor of the fovea magna merges into the outer admedian plane. The upper 
end of this plane is cut off obliquely by the almost straight boundary of the supra- 
alveolar process. 
The symphysial face is very narrow, broadening slightly for a short distance 
above and for a longer distance below to about 0°25 mm. The length of the sym- 
physis is 8:0 mm., the full height of the hemi-pyramid being exactly 9:0 mm. The 
union therefore is through 0°88 of the whole length, precisely as given by Loven 
for Cidaris papillata (Echinologica, p. 52). 
The internal face (fig. 225) shows a very narrow central canal. Lineae emi- 
nentes not strongly pronounced, surrounding a slightly concave dental slide, and 
ending in a very faint styloid process. Above this the dental sulcus continues, 
bounded by a slight ridge, which ends in the angle of the supra-alveolar process. 
Ferussdlemhegy (c). 
A fragment from the adoral end of a left maxilla. Raiblian. 
This is probably of the same species as b, from which it differs in the thicker 
symphysis, O'4 mm. wide. 
‘erussdlemhegy (d). 
(Plate IX. figs. 226—228.) 
A right maxilla. Raiblian. 
Interpyramidal joint-face (fig. 226) 6°3 mm. long, greatest width at aboral 
end 36mm. Aboral margin slopes inwards and downwards (as usual in Cidaridae). 
The transverse ridges have a slightly greater downward slope with a simple curve, 
convex downwards; 6 or7to 1mm. Fossa arcualis wide, being 1°7 mm. at base of 
supra-alveolar process, which is 2°3 mm. high. 
9* 
