BY N. DE MIKLOUHO-MACLAY. 573 



The under surface of the lateral incisors is an oval flat groove, 

 surrounded with a cuspidated margin. The exterior margin is 

 divided in both teeth into 4 distinct cusps, which are characteristic 

 of the incisors of this species. 



Incisors. The size of the first (central) incisor, compared with 

 the lateral ones, shows less "difference in Dorcopsis Chalmersii than 

 in D. luctuosa, and the second incisor of the former is, relatively 

 to his neighbours, not so small as in the latter species. 



In the second right incisor the incision between the median 

 cusps, extends in a vertical ridge, (fig. 8) which is not marked in 

 the corresponding (left) tooth of the other side. (Fig. 7.) 



The canines are in D. Chalmersii, relatively to the other teeth, 

 smaller and shorter than in D. luctuosa. 



The temporary premolar, measured on the neck, is only a little 

 more than half the breadth of the permanent one [the first being 

 9 mm. or 0-4 inch, the second 16 mm. or 0*65 inch.] On the 

 cutting edge 4 cusps are distinguishable, of which the first (the 

 anterior) is the most marked. These cusps are the ends of vertical 

 ridges which run from the base (the cingulum) on the internal as 

 well as on the external side. 



The permanent Premolar (fig. 9, A.-E.) which I dug out of its 

 formative cell, showed a breadth (16 mm.) just equal to the breadth 

 of the temporary premolar and the temporary molar together. 



On the external side, 7 ridges ending in the same number of 

 cusps may be distinguished, of which however, only 3 are well- 

 marked. On the internal side, the ridges, with the exception of 

 the first (or the anterior), are less apparent than on the external 

 side. On the posterior end of the tooth, behind the cutting edge, 

 appears a tubercle, the cusp of which is lower than the edge. A 

 smaller tubercle is to be found on the base corresponding to the 

 second, anterior ridge on the internal side of the premolar. 

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