100 DR. R. BROOM ON THE [Feb. 7, 



pectineal process entirely, or a process for the attachment of a 

 cartilaginous prepubis, the evidence does not show. The sym- 

 physial portion is typically mammalian. 



The ischium is, on the whole, fairly like that of the mammal. 

 The acetabular portion is large, and there is no evidence of a 

 cotyloid notch in the articulation. A little distance below the 

 articular portion the bone is considerably constricted, and then 

 widens out into a broad fan-like expansion. The posterior border 

 of the b(Ae is nearly straight, being only slightly concave at its 

 upper part. It is fairly broad and slightly hollowed out. Pro- 

 bably the anterior half of the lower border of the bone formed 

 part of the symphysis with its neighbour. If this is so, then the 

 pait of the symphysis formed by the ischium in Diademodon 

 would be considerably less than in Cynognathws. 



The obturator foramen is of large size, as in mammals 

 generally. It is relatively about as large as in Echidna, and 

 I'ather larger than in Gynognathus. 



The following are some of the principal measurements of the 

 pelvis : — 



millim. 



Antero-posterior length of iliac crest about 68 



From lowest point of ilium to nearest point of 



iliac crest 40 



Width of acetabular portion of ilium 30 



Greatest length of pubis 38 



Greatest length of ischium 47 



The femur is fairij well preserved, and is especially interesting 

 since the Theriodont femur has not hitherto been very well 

 known. The imperfect proximal end of the femur of Cynognathus 

 has been described by Seeley, and he has also described a fairly 

 good femur of Triholodon showing the anterior and outer 

 surfaces. The femur of Diademodon as developed shows the 

 posterior, outer and inner sides, so that it fills up the blanks in 

 our knowledge of the bone. The proximal end of the femur is, 

 as in Gynognathus, greatly expanded owing to there being no neck, 

 and the large trochanter major being thus continued on to the 

 articular head. If we regard the condyles as pointing backwards, 

 then the expanded proximal end of the bone is directed backwards 

 and outwards from the head, and the trochanter major, which 

 forms the outer end of the expansion, points almost directly out- 

 wards. There is thus left in front of the trochanter a concavity. 

 Along the posterior pai't of the inner side of the upper third of 

 the shaft there is developed a prominent ridge which is directed 

 backwards and slightly inwards. Superiorly it ends abruptly about 

 the level of the lower part of the head and forms the trochanter 

 minor. It will thus be seen that the upper part of the Therio- 

 dont femur bears a gi-eater resemblance to that of the mammal 

 than to that of either the Therocephalian or Anomodont. In 

 Oudenodon the proximal end of the femur agrees with that in 



