Structure and Affinities of the Eudothiodont Beptiles. 261 



dontia, of the order Therosuchia, one of the two principal orders into 

 which he divides the Anomodontia. 



Within the last few years the only papers dealing with the 

 Endothiodonts have been one or two by myself (7, 8, 9, 10, 11), 

 dealing with certain points in the anatomy, and describing a few 

 new forms. As, however, a considerable number of new specimens 

 have been discovered, it is now possible to give a pretty complete 

 account of the structure of the skeleton of the Endothiodonts. 



Endothiodon bathystoma, Owen. 



About a year ago Mr. J. M. Bain presented to the South African 

 Museum a number of fossil bones collected by his father, Mr. T. 

 Bain, many of which are of great interest. Perhaps the most 

 important specimen is the greater part of a skeleton of Endothiodon 

 bathystoma. There are preserved the antorbital portion of the skull, 

 the front half of the lower jaw, the parietal crest, the greater part of 

 the occiput, and two fragments of the arches. Of the vertebrae there 

 are preserved 19 of the presacral series and 4 sacral vertebrae. It is 

 possible that all the vertebrae from the first to the seventeenth in- 

 clusive are preserved, but there are three points in the series where 

 there may be a break. Immediately behind the axis, one, or possibly 

 two, vertebrae may be missing. On the other hand it is quite 

 possible all the cervical vertebrae are present. Breaks occur between 

 the fifth and sixth, and between the fifteenth and sixteenth vertebrae, 

 but it is improbable that any vertebrae are missing at these points. 

 Behind the seventeenth vertebra there are evidently a number of 

 vertebrae missing, only two being preserved out of possibly seven. 

 The two may be the twenty-second and the twenty-sixth. The 

 sacrum is composed of four vertebrae, all of which are present and 

 fairly well preserved. Of the shoulder girdle there are only pre- 

 served the upper and the lower part of the right scapula, and a 

 fragment of the right precoracoid. The proximal half of the right 

 humerus is preserved. The pelvis is fairly well preserved, both ilia 

 being practically complete, and the upper parts of both pubes and 

 ischia being present. The proximal and distal ends of both femora 

 are preserved with the proximal ends of the tibia and fibula of 

 both sides. 



In addition to this very fine specimen there is in the South 

 African Museum the anterior part of the mandible of another 

 individual. 



The chief new features that are revealed in the structure of 

 the skull are the great width of the occiput, and the presence of a 



