140 



Annals of the South. African Museum. 



meet each other in the middle Kne, and hoth articulate with the small 

 interclavicle which, to some extent, is fitted in between them. From 

 their median union the clavicles pass first backwards and outwards, 

 and then somewhat more directly outwards. The outer ends of the 

 bones are missing. 



The interclavicle is very much smaller than that known in any 

 other Anomodont. In Dicynoclon it has a long median process, 

 somewhat resembling that in Procolojjhon, though considerably 

 smaller. In a small as yet undescribed Endothiodont allied to 



Fig. 1. 



Fig. 2. 



Fig. 1. — Left scapula of Lystrosaurus sp. ? x •45. 



Fig. 2. — Sternum, clavicles, interclavicle, precoracoid and portion of coracoid of 

 Lystrosaiints sp. ? x "52. 



ac. acromion; cl., clavicle; co., coracoid; id., interclavicle; pen., notch for 

 precoracoid foramen; j'-c^)-, precoracoid; at., sternum. 



Pristerodon the interclavicle is a median broad plate only a little 

 smaller than the sternum. In Lystrosaurus we find it as a small 

 triangular bone which fits in front in between the inner ends of the 

 clavicles, and behind articulates apparently with the front of the 

 sternum. From the posterior border, which is rounded, the bone 

 passes forwards and markedly downwards, forming a prominent 

 median boss, a,nd it is this anterior part that articulates with the 

 clavicles. 



