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9. — On the Milk Dentition of Orycteropus. — By E. Broom, M.D., 



D.Sc, C.M.Z.S. 



There is probably at present no living mammal whose affinities are 

 more in donbt than Orycteropus, the Aard Vark of the South African 

 farmers. Though placed among the Edentates, it has long been 

 recognised that it has very little affinity with the typical American 

 forms ; and while it seems to resemble more closely the Old World 

 Manis, it is doubtful if the slight resemblance indicates a relation- 

 ship. 



In 1890 Oldfield Thomas made an important advance in our 

 knowledge of Orycteropus by his discovery of milk teeth in two 

 young specimens in the British Museum. "Each of these speci- 

 mens has a complete, although rudimentary, set of milk teeth, 

 extending the whole length of the maxillary bones above, and 

 along a rather shorter portion of the mandible below. None, 

 however, are observable in the premaxillse, or in the corresponding 

 anterior part of the mandibles. The teeth are all quite minute, and 

 it is very doubtful whether they would ever have cut the gum.'' 



" In the upper jaw there appear to be normally no less than seven 

 milk teeth. Of these the most posterior is by far the largest, has a 

 rudimentary crown, and two distinct roots, anterior and posterior. 

 The second, proceeding forwards, is far smaller, and is simple and 

 styliform. The next, the third from the back, is also simple, but is 

 far larger in section, and its base is not closed up in either of the 

 specimens ; on this account there seems to be just a possibility that 

 this particular tooth is not a milk tooth at all, but only the tip of one 

 of the smaller anterior permanent teeth, which it resembles closely 

 in size ; on the other hand, however, its complete calcification is in 

 marked contrast to the soft condition of the other permanent teeth, 

 and therefore it seems safer for the present to call it a backward 

 milk tooth rather than a precocious permanent one." 



" In front of the three posterior teeth there are normally four 

 very minute styliform ones, similar to, and equidistant from each 



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