from the Karoo Beds, South Africa. 315 



in the Lower. In its general form and proportions the 

 resemblance to the jaw of Tribolodon from Lady Frere (Phil. 

 Trans. 1894, B, pi. lxxxviii. fig-. 6) is very marked. The 

 horizontal ramus of the jaw is long and rather slender and 

 moderately uniform in depth. The coronoid process is very 

 well developed, long and fairly thick, and makes an angle of 

 about 120° with the ramus. Almost the whole lower jaw 

 appears to be formed by the dentary, the splenial being a 

 feeble splint and the articular, which is lost, probably not 

 large. 



Perhaps the most remarkable feature of the form is the 

 simple structure of the teeth. Seven teeth still remain in 

 the jaw, and though it is possible that one or two others are 

 lost, those that remain show that there is no marked distinc- 

 tion between incisors, canines, and molars, all the teeth being 

 modifications of the simple pointed Saurian type. All the 

 teeth are feebly ribbed, and the anterior teeth differ from the 

 posterior only in being longer and moderately sharp, while 

 the latter have rounded apices. 



The fragment of the maxilla shows the upper teeth to be 

 very similar to those of the lower jaw. 



The scapular arch resembles that of Rhopalodon (Phil. 

 Trans. 1894, B, p. 70-i) more closely than that of Dicynodon. 

 The scapula, while expanded and flat above, is narrow in the 

 middle. There is no very distinct acromion. Inferiorly the 

 scapula is much expanded and forms a large articulation with 

 the precoracoid. The precoracoid is considerably larger than 

 the coracoid and differs from that in Dicynodon in not 

 entering into the glenoid cavity and in completely surrounding 

 the precoracoid foramen. The coracoid closely resembles 

 that in Dicynodon. 



The humerus is very mammal-like and bears considerable 

 resemblance to that of Gomphognathus (Phil. Trans. 1895, B, 

 p. 29), though less robust. There is a large epicondylar 

 foramen, and the whole lower half of the bone so far as is 

 preserved is much like that of the Phalangers. Above, there 

 is a sharp delto-pectoral crest, somewhat less prominent than 

 that in Gomphognathus , because less directed outwards from 

 the bone. 



The femur is slightly longer than the humerus, and, like it, 

 shows much resemblance to the mammalian types. There is 

 a well-marked great trochanter, which forms a prominent 

 trochanteric ridge more resembling the condition in some of 

 the "Edentates and Marsupials than that of either of the 

 Monotremes. On the whole, however, the affinities of the 

 bone are mainly with the type seen in Echidna ; and if the 



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