BUFFALO SOCIETY OF NATURAL SCIENCES 9 
to this peculiar structure in my description of the brain case and 
palate. This portion of the head-shield is illustrated in Plate 5, 
fig. 2; and fig. 3 on the same plate shows to good advantage the 
shape of the interfrontal. Two large premaxille in advance of 
the interfrontal fuse with it and with the two small nasals to form 
a continuous shield over the snout, in which the sutures are exter- 
nally almost entirely obliterated. The external nostrils are locat- 
ed in the premaxille, slightly in advance of the nasals. In one 
specimen I have seen indications of another small polygonal bone 
wedged in between the interfrontal, the nasal and the premaxilla, 
but as | am not certain about it I have not indicated it in my 
restoration. The rather small orbits are bounded above by the 
narrow prefrontals which are curved to conform to their shape. 
On Plate 2, fig. 1, I show a rat'-er well preserved skull which 
exhibits very clearly the position of the eye and of the external 
nostril. Figs. 2 and 3 on the same plate show that the eye was 
defended by an inner ring of true sclerotic plates which are closely 
articulated, and conform to the shape of the eye-ball. The nos- 
tril is seen to be located some distance in front of the eye and is 
laterally, not ventrally, directed. 
Behind the orbit is a large bone, the postorbital, which is in con- 
tact dorsally with the frontal and is continued as a narrow wedge 
between the intertemporal and a large cheek plate, usually named 
the squamosal. It also articulates with the prefrontal and below 
with the jugal. The squamosal is the largest of the cheek plates. 
It is so firmly united to the preoperculum and to the quadratoju- 
gal that the sutures can only be detected by an examination of 
their inner surfaces. This aspect is shown on Plate 5, fig. 1, and 
the preoperculum and quadratojugal in this species have never 
before been positively recognized. It is probable that better ma- 
terial would show their presence in all of the members of this 
family although they are said to be absent in Gyroptychius and 
Osteolepis. 
The preoperculum is an elongated bone, narrow above, artic- 
ulating behind with the large operculum and suboperculum and 
below with the quadratojugal, in advance of which is a long and 
slender maxilla. The remainder of the cheek above the maxilla 
is occupied by two large bones, the jugal and the lacrymal, the 
latter of which forms the lower border of the orbit and is in con- 
tact besides with the prefrontal, nasal and premaxilla. 
Wedged in between the squamosal, the operculum, the tabular 
