30J: Mr. D. ^I. S. Watson on 



The posterior part of each ramus is well preserved. 



The articular is a large bone ; its condyle is damaged by 

 excessive development, but it must have greatly resembled 

 that of Dimetrodon. There is no appreciable postarticular 

 process. The outer surface of the bone is completely 

 covered by the suraugular, which is separated by visible 

 suture. The inner surface is to a large extent covered by 

 tiie prearticular, which, however, does not touch the sur- 

 augular, so that a sharp narrow ridge of articular is visible 

 from below. 



[I think it probable that a considerable part of the present 

 outer surface of tiie surangular was formerly covered by the 

 angular, which may have been stripped oif during develop- 

 ment.] 



Atlas. 

 The intcrcentrum of the atlas is well preserved ; it forms 

 a short broad band across the basioccipital condyle, whose 

 j)osterior outer corners carry ribs. The neural arches of the 

 atlas and, I think^ but am not sure, a proatlas are present, 

 very much crushed. 



Veiiebrce. 



One feature of the vertebra}, already described ])y 

 Dr. Broili, deserves to be enij)hasized ; this is the relative 

 heaviness of the neural arches and the fact that the articu- 

 lating faces of the zygapophyses are horizontally placed. 



Ribs. 



The ribs appear to have been holocephalous tliroughout 

 the column, witli, perhaps, the exception of a few anterior 

 pairs. Some of the ribs in the region of the jjcctoral girdle 

 arc flattened and expanded, like those of many cotylosaurs. 



Pectoral Girdle. 



Tlic cartilaginous part of the left side of the shoulder- 

 girdle is very well preserved, except for the upper end of the 

 scapula. 



It is extraordinarily like that of Ophiacodon as figured by 



Williston. 



The scapula is a broad thin Ijone, thielvcned at its poste- 

 rior edge, rising from the border in the powerful process 

 which supports the anterior part of the glenoid cavity. Tlie 



