NEW REPTILES FROM THE UPPER TRIAS 693 



The ilium extends upward and forward in a broad curve. The 

 upper portion is broad, fiat, and rather thin. The distal part had been 

 broken off before fossihzation, and the attaching fracture so corroded 

 and incrusted with matrix, removable with difficulty from the thin 

 bone, that its precise relations are somewhat doubtful. This portion 

 has been omitted in the photograph, but the free, thin, concave border 

 seems to continue the curve before it for about eight inches, the distal 

 portion being somewhat dilated and very thin. Such a shape is most 

 extraordinary for an ihum. This part of the ihum turns outward as 

 though for the protection of the abdominal walls. The posterior 

 border of the ilium was unfortunately lost before the presence of the 

 bone was suspected, lying as it did below the scapula. It was evi- 

 dently thin. 



The acetabulum forms a deep oval cavity, somewhat notched at 

 the upper posterior part. The pubis was directed obhquely inward, 

 and has a strong, everted, articular face, perhaps for an epipubis or 

 prepubis, very much as has been figured in species of dicynodonts.^ 

 A little in front of the middle, and about two inches below the rim of 

 the acetabulum, there is seen a short, free margin, evidently the upper 

 margin of the thyroid (obturator) foramen, and in all probability 

 situated in the line of the suture between the pubis and ischium, 

 since both bones were broken apart in this same place. The border 

 connecting the pubic and ischiadic angles has not yet been recon- 

 structed, but patient labor will doubtless fit in the whole of this 

 portion from the many thin fragments preserved in each of the 

 specimens. 



The pubis and ischium are turned inward tow^ard the median 

 line. 



Lying upon the distal part of the humerus there was a small bone, 

 about six inches in length, which seems to be a sacral rib, resembhng 

 as it does the corresponding bones of some dinosaurs. 



mm 



Length of humerus - ------ 440 



Greatest width across lateral process - - - 237 



Breadth, lower end of lateral process . - . - 182 



Least diameter of shaft ------ gg 



Greatest width, distal end ------ 263 



Tapinocephalus, Lydekker, Catalogtie of Fossil Reptiles, British Museum, IV, 82. 



