50 NEW REPTILES AND STEGOCEPHALIANS PROM 



described below. The lateral temporal openings are elongate and inclined downward 

 and forward, reaching as far forward as the center of the orbit. The antorbital openings 

 are elongate and rather narrow vertically; they reach from just anterior to the orbit 

 to a point below the center of the narial opening. Both the lateral temporal openings 

 and the antorbital openings are but partially visible from above. 



The parietal bones are small, each with a slender process extending outward and 

 backward and forming the upper edges of the deep notch at the posterior end of the 

 skull. These processes form the inner borders of the upper temporal openings and ter- 

 minate near its posterior end. The anterior portion of each parietal meets its fellow of 

 the opposite side in the median line; the extent forward is not accurately made out, but 

 it is, in all probability, not great. This portion of the parietal forms the anterior edge 

 of the upper temporal opening. There is no trace of a parietal foramen. 



The squamosals are cruciform in outline. The anterior arm unites with the postor- 

 bital to form the bar between the two temporal openings. The inner arm is very narrow 

 and unites with the parietal; the outer arm is much wider and is overlapped by the upper 

 end of the quadratojugal. On the lower surface of this arm there is a concave surface, 

 elongate laterally for the reception of the upper end of the quadrate; this is clearly shown 

 on the left side, where the quadrate is missing, having been lost by maceration before 

 the fossilization of the skull. The posterior arm is short; its upper surface is marked 

 by prominent rugose ridges extending in the direction of the greatest length of the bone. 

 The posterior end overhangs the distal end of the opisthotic. 



The postorbital forms a small part of the posterior edge of the orbit and articulates 

 with the jugal below. It sends backward and slightly outward a broad arm which unites 

 with the squamosal. Just anterior to the suture there is a broadening of the outer side 

 which forms a constriction in the lateral temporal foramen. 



The outlines of the frontals, postfrontals, prefrontals, and nasals can not be made 

 out clearly. This portion of the skull is rugose and is badly broken and cracked, the 

 cracks being filled with limonite, so that the sutures can not be followed. The probable 

 course of the various sutures is indicated in dotted lines in the figures. It seems alto- 

 gether probable that the nasals had considerable extent posterior to the narial opening. 

 Dividing the narial opening some distance below the upper edge of the rim, there is a 

 slender rod formed by two narrow, elongate bars which meet in a close, relatively broad 

 symphysis, as shown in figure 21. This septum is, in all probability, formed by the 

 anterior ends of the nasals. 



The septomaxillaries. No trace of these elements could be found, but it may well 

 be that the limiting sutures are obscured in the specimen. 



The premaxillaries form the greater part of the long, slender rostrum anterior to 

 the narial opening. The origin of the maxillary-premaxillary suture lies about 3 centi- 

 meters in advance of the opening ; the suture is traceable backward between the two bones 

 and then is apparently continued backward between the premaxillaries and the nasals, 

 allowing the premaxillaries to take a small part in the anterior portion of the rim of the 

 nares; this last point is, however, uncertain. The anterior ends of the premaxillaries 

 are only very slightly thickened and expanded to accommodate the alveoli of the anterior 

 teeth. The rugosity of the upper surface terminates with the narial opening and the 

 surface of the maxillaries and premaxillaries is relatively smooth. The quadratojugal, jugal, 

 maxillary, and lachrymal are only obliquely and imperfectly exposed in the upper view. 



The side of the skull (plate 11, fig. B). The small extent of the projection of the 

 squamosal beyond the quadrate and occipital condyle is very noticeable in this view. 

 The posterior process of the squamosal is excavated below, so that the whole projection 

 is thin and without a terminal descending portion. In the notch below can be seen the 

 distal extremity of the opisthotic. 



