20 NEW EEPTILES AND STEGOCEPHALIANS FROM 



is very puzzling in places; towards the outer ends the three seem to be indistinguishably 

 fused; this may be natural or may be due to the very close approximation of the elements, 

 partly due to a very slight compression in fossilization. It is possible that the descending 

 process was surrounded by cartilage and that the partial ossification of this cartilage 

 may have produced the appearance of fusion of the bones. The thin outer edge formed 

 by the united or approximated ends of the processes descends obliquely forward and 

 disappears behind the quadrate; there is a small foramen between the bones at this point. 



The quadrate. The upper surface of the quadrate was seen in the specimen during 

 preparation; it sends a shorter and heavier process backward and inward to articulate 

 with the posterior process of the pterygoid, and a longer and more slender process for- 

 ward which lies on the anterior face of the anterior process of the pterygoid. This 

 anterior process is expanded vertically and in life was either applied closely to the 

 pterygoid or attached to it loosely by cartilage. In the specimen it is separated from 

 the pterygoid on both sides by a space of a millimeter or two, now filled with matrix. 



The exoccipitals. These join the pterygoids and the parasphenoids by finely inter- 

 digitating sutures. The edges of the parts of the exoccipitals, which form the walls of the 

 brain-case, are broken away, but they did not rise to and connect with the roof, as is 

 proven by the absolutely smooth surface of the under side of the roof-bones. Anterior 

 to the rising process there is a foramen; a little farther forward and somewhat laterally 

 there are two small foramina on the left side and a single foramen on the right side. At 

 the base of the rising process on the posterior outer angle there is a small foramen. On 

 the right side there is a second foramen on the posterior inner corner, but this is lacking 

 on the left side. 



The lower surface of the roof of the cranial area (fig. 3). -The dermsupraoccipitals 

 and the tabulare send down processes which unite with the rising processes of the exoc- 

 cipitals. On the inner side of these processes there is a thin plate of bone, evidently 

 the very rudimentary opisthotic. On each dermsupraoccipital there is a small, elongate 

 area with a rough surface and slightly raised edges; that of the left side reaches to and 

 even crosses the dermsupraoccipital-squamosal suture; that of the right side is shorter. 

 These are evidently points of cartilaginous attachment for some element of the brain- 

 wall, probably the prootic, but no trace of such an element was preserved. The tabulare 

 has small presentation on the lower surface and the outline is nearly square. About 

 the center of the bone there is a deep pit with the inner edges slightly elevated. These 

 pits end blindly and do not penetrate more than halfway through the bone. Outside 

 of the pits the remainder of the surface is rough and evidently afforded cartilaginous 

 attachment; the rough area terminates sharply at the tabulare-squamosal suture, but 

 the adjacent portions of the squamosal are marked with fine grooves, as if by a plexus 

 of blood-vessels. There is no element which can be supposed to have attached to this 

 area, unless it be the opisthotic, which has nearly disappeared in the genus; this sugges- 

 tion seems the more unlikely, as, if it were attached, the opisthotic would appear on the 

 posterior face of the skull, which it does not do in the Metoposauridse. On the other 

 hand, Watson 1 shows an ascending plate on the inner edge of the exoccipital in Capito- 

 saurus. The thin plate on the inner side of the rising process of the exoccipital of 

 Buettneria may possibly be such a process, though it is apparently free from the exoc- 

 cipital and has been interpreted as the opisthotic. The meaning of the large pits on the 

 tabulare is not understood. 



Attached to the inner edge of the anterior rising process of the pterygoid there was 

 found, on the left side, a small plate of bone, somewhat constricted in the middle. This 

 lay vertically in the matrix and extended horizontally inward, across the posterior end 



1 Watson, D. M. S., loc. cit., fig. 11 A. 



