574 ON A NEW SPECIES OF KANGAROO (DORCOPSIS CHALMERSIl), 



The temporary molar. Though in general, presenting the 

 character of the permanent molar, the temporary molar is smaller 

 in size, and shows a marked difference from the molars, in the 

 shape of an elongated anterior and external cusp, which gives the 

 tooth, examined from the outside, a somewhat premolar-like 

 appearance. 



The Molars of D. Chalmersii do not present any special 

 deviation from the general type of Molar teeth of Macropodidse. 



Teeths of the lower jaio. (Fig. 6.) 



Incisors. — Rather long and narrow, terminating not in a point, 

 but with a horizontal edge of 1J mm. breadth. 



The temporary premolar, smaller than the corresponding tooth 

 of the upper jaw ; 4 cuspidate and 4 ridged, with the cutting edge 

 slightly convex outwards. 



The permanent premolar. (Fig. 9, A.-E.) The under jaw being 

 much harder than the maxillary bone, as well as on account of the 

 fangs of the temporary teeth, it was not easy to get the permanent 

 premolar out of its formatory cell. Not having sufficiently delicate 

 instruments and fearing to destroy not only the jaw but the tooth, 

 I thankfully accepted the kind assistance of Mr. P. R. Pedley, who, 

 after fully 45 minutes of filing and breaking away, succeeded in 

 making the tooth free without the slightest injury. The premolar of 

 the under jaw showing a general resemblance to the corresponding 

 tooth of the upper jaw is shorter, (12^ mm. on the neck and 

 10 mm. between the extreme cusps), and on the cutting edge 

 only 6 cusps ar*e visible, corresponding to the number of vertical 

 ridges on the external and internal side of the tooth. Another 

 distinction from the premolar of the upper jaw is the absence of 

 tubercles on the internal side of the mandibular premolar ; the 

 tooth consists only of a cutting edge, like the temporary premolar. 



The temporary Molar. Very different from the other molars, 

 consists of an elongated premolar-like anterior half and a 



