THE UPPER TRIASSIC OF WESTERN TEXAS. 



21 



of the groove on the upper face of the posterior end of the pterygoid. It is perhaps an 

 ossification of the alispenoid or orbitosphenoid cartilage; no corresponding element was 

 found on the other side. 



One of the remarkable features of the skull is the evidently large amount of cartilage 

 in the walls of the brain-case. The stapes were lost and the otic opening is very large, 

 the bones around it terminating in smooth edges. There seems no escape from the 

 conclusion that the whole of the area of the organ of hearing was cartilaginous. The 

 whole of the lower surface of the bones in the area occupied by the brain is perfectly 

 smooth, with the exceptions noted. There was no attachment of exoccipital, epiotic, 

 or opisthotic to the upper wall, and the same condition in front shows that there 

 was no ossification of the ethmoidal elements. 



FlG. 3. — Buettneria perfecta. 



View of lower surface of roof-bones of cranial 

 region. 



x', rugosity showing place of attachment of 

 the prootic; x, rugosity showing 

 place of attachment of the anterior 

 rising process of the pterygoid; 

 opf, opisthotic. Other lettering as 

 in figure 1. 



The teeth are imperfect, the tops having been broken away and the stubs worn 

 as the skull was dragged, palatal side down, over the bottom. In even the smaller 

 teeth the broken surfaces show the labyrinthine structure (plate 2 b). 



It is evident that this genus has its nearest relations in Metoposaurus and belongs 

 in the family Metoposauridae of Watson, 1 but it is very doubtful whether Anaschisma 

 can be retained in the same family. From Metoposaurus the genus Buettneria differs in 

 the narrower processus cullriformis and the shape of the posterior portion of the para- 

 sphenoid, in the smaller (or absent) transverse, in the shorter quadrate ramus of the 

 pterygoid, in the loss of all trace of the post-temporal foramina, in the presence of a 

 series of small teeth on the internal nares, etc. 



Measurements. — Total length of skull, 443.2 mm. Breadth of skull at posterior 

 end, 344.2 mm. 



For this new form I take great pleasure in proposing the name Buettneria perfecta, 

 in recognition of the interest, patience, and skill of Mr. William H. Buettner, who has 

 prepared the skull and mounted it in all of its perfection. 



A second skull of the same genus, but far less perfect, showing only the upper 

 surface, was found in the same region. Many other isolated bones were found, indicating 



1 Watson, D. M. 8., loc. tit., p. 07. See also v. Huene, Gonioglyptus, ein alttriasicher stegocephale aus Indien, 

 Acta Zoologica, p. 456, 1920. In this paper v. Huene arrived, independently, at almost exactly the same 

 arrangement of the families of the Stegocephalia as did Watson a year earlier. 



