148 ON TWO NEW SPECIES OF DORCOPSIS, 



cusps of the third (1). On the external surface of the tooth, from 

 the cinguhim several ridges with intervening depressions run at 

 right angles to the cutting edge which in D. Beccarii is a little 

 curved and not so distinctly cuspidated as in D. luctuosa. The 

 anterior part of the tooth, examined from the external (labial) side 

 is a trifle higher than the posterior. On the internal (lingual) side, 

 the ridges and the depressions are less marked. 



Examined from below (looking at the base of the skull) tlie 

 external and internal outlines of the premolar, are not quite 

 parallel, but there is an inflection noticeable on the internal outline 

 which corresponds also with the narrowest transversal diameter of 

 the tooth. 



Out of the 4 molars, only the first is a little worn down as well 

 as the cusps of the second. The fourth molar is the smallest and 

 the posterior portion (cusp) of the same is smaller than the anterior, 

 in which peculiarity the fourth molar differs from the other molars 

 which have the two portions (cusps) nearly of the same size. 



In D. Beccarii, the molars with the premolars form not two 

 parallel straight, but two slightly curved lines converging more 

 behind than in the front. [The distance between the two most 

 prominent points of the internal side of the premolar being 18 mm., 

 and that between the corresponding joints of the molars 15 mm. (2)] 



In the lower jaw, the incisors are rather narrow and straight. 

 The Premolars are scarcely less broad than in the upper jaw, and 

 present the same proportion of breadth in relation to the first, 

 second and third molar of the lower jaw as in the upper. 



The slightly cuspidated cutting edge of the Premolar, examined 

 from the side, is curved, the posterior end being the highest point 

 of the same ; viewed from above, the edge is also not straight, but 

 convex outwards. Similar to the upper Premolar, the inner 



(1) The size of the premolars of D. luchwsa, in comparison with the size 

 of the molars, present exactly the same proportion (Vide Garrod, On Halma- 

 turus luctuosa, etc., etc. Loo. cit., p. 54.) 



(2) This case proves that the arrangement of the teeth, premolars and 

 molars, on both sides of the upper jaw, forming straight lines parallel one 

 to the other, cannot, as Garrod supposed (loc. cit., p, 53), be regarded as a 

 constant cranial character, which distinguishes Dorxopsiti as a genus from 

 Macropus, 



