FAUNE DU CALCAIRE CARBONIFÈRE DE LA BELGIQUE. 
21 
margin of lhe clavicle of the other side is brought into view. It is hardly possible to make out tbe 
infraclavicular plate, though, as in allied forms it doubtless was also présent. The external ganoid 
surfaces of the above-described shoulder bones are ornamented with sharp and délicate ridges, 
branching, anastomosing and intercalated whose direction is mainly parallel with the long axes of 
lhe bones themselves. 
Seules. — The scales of the body are, as usual, arranged in oblique and slightly sigmoidal 
dorso-ventral rows or bands, of which 55 may be counted from the shoulder to the commencement 
o( the tail pedicle, whcnce onwards, the posterior part of the fish exists only as a nol very well 
preserved impression. Those of the front of the flank are higher than long, the upper margin 
shewing a shallow notch or excavation in front, and the lower has a corresponding rounded pro¬ 
jection. Unfortunately the entire contour of a scale cannot in any case be seen, not one being found 
dislocated from its original position. It is therefore impossible to détermine the position and degree 
of development of the keel of the attached surface or of the articulai’ spine of the upper margin, 
but lhe general aspect of the scales is such as to lead one to conclude that in these respects they 
conformed to the type most usual in the Platysomidæ. The covered area of the scales is pretty 
extensive; the free or sculptured one is very distinctly marked off, and is ornamented by délicate 
closely set raised striae, or ridges, which pass rather obliquely downwards and backwards over the 
surface; a certain number, however, of those on the lower part of the area, proceeding more directly 
backwards and parallel with the lower margin, meet the others consequently al acute angles. 
Posteriorly, and towards the dorsal and ventral aspects the scales become more équilatéral, and 
tlieir striae more feebly marked. The médian scales of the back are small and inconspicuous as far 
as the 26"’ oblique band behind the shoulder, but thence backwards to close to the commencement 
of the dorsal fin, they become three or four times as large, with acute posteriorly directed points 
forming a conspicuous line reminding us of the row of dorsal médian scales in Ischyplerus or 
Semtonotus . The ventral margin, between the pectoral and ventral fins is covered with a peculiar 
set of elongated scales, whose long axes pass obliquely downwards and forwards at an angle to the 
oblique bands of body scales above them, except just in the neighbourhood of the pectoral fin, 
whcre the dorso-ventral bands alreadv turn round and pass obliquely downwards and forwards, 
before the elongated scales corne on. The scales of the caudal body-prolongation are, as usual, 
arranged in oblique bands proceeding from above downwards and forwards; they are very small 
and losengeshaped ; the condition of the ridge-scales of the dorsal margin of this prolongation is 
not shewn. 
Fins. — Only a portion of the pectoral is preserved, but, from what is seen of it, it may be 
judged to hâve been rather small. Neither its latéral margin nor its extremity are seen; its base 
seems to bave been covered with small scales ; and about 24 délicate rays may be counted. Tbe 
ventral is placed rather far back, arising 3 '/„ inches from behind the origin of the pectoral while 
only 1 % interverses between il and the commencement of the anal; it is also small, but such of 
its rays as are preserved are rather coarser than those of the pectoral. The dorsal arises 6 V 4 inches 
from the extremity of lhe snout, its commencement being thus placed considerably behind the 
middle of tbe arch of tbe back and only slightly in front of the origin of the anal. It is shaped very 
much like the dorsal fin of Eurynotus, its contour being high and acuminate in front. Then fal- 
ling away more gradually till posteriorly, it assumes a fringe-like aspect and terminâtes at the rise 
