290 



Majesty's Ship 'Galatea,' under the command of His Royal Highness, and exhibited in 

 the South Kensington Museum. The molar teeth in this fossil arc in a more perfect 

 state of preservation than in any other Nototherian jaws which had previously come 

 under my observation ; and, being from an individual of the same age as that to which 

 the jaw and teeth of Nototherium Victoria; from South Australia belonged, they exemplify 

 more plainly and completely the differential characters of that species and of the Not. 

 Milch el 'li from the Province of Queensland. 



The teeth (m i, a, 3) of Nototherium Mitchelli differ from those of Not. Victoria; in the 

 presence of a " cingulum" on the outer side of their base (comp. figs. 2 & 3, c, Plate XLV. 

 with figs. 4 & 5, Plate XLIV.). In m 1 the cingulum is continued from the prebasal ridge 

 (fig. 2,f) along the base of the anterior lobe to the outer tubercle (A), closing the valley, 

 upon the outer surface of which the cingulum subsides ; but it resumes its course behind 

 the tubercle along the outer side of the posterior lobe (b), where it is continued upward 

 along the middle of that side ; but from the base of this vertical prominence (d, fig. 2, 

 Plate XLV.) the cingulum is continued to the postbasal ridge (g), which, like the prebasal 

 one, is a more developed part of the cingulum. In Nototherium Victoria; the cingulum 

 is represented only by the pre- and postbasal ridges (Plate XLIV. figs. 4, 5, 6, f\ g), and by 

 the closing tubercles (ib. h, h') before mentioned (p. 77), at the outer and inner ends of 

 the transverse valley. The penultimate molar (m 2, Plate XLV.) presents the same differ- 

 ential characters. In m 3 of the present specimen of Nototherium Mitchelli the vertical 

 continuation from the cingulum upon the outer side of the hinder lobe is not present 

 (Plate XLV. fig. 2, ms); but in Not. Victoria; the outer closing tubercle (Plate XLIV. 

 fig. 4, m b, h) and the postbasal ridge (ib. g) are both extended, converging, to curve up 

 along the outer side of the hinder lobe of m 3, without crossing its base, as does the cin- 

 gulum (Plate XLIV. fig. 2, m 3, c) in Not. Mitchelli. All the molars in Not. Victoria; 

 differ from those in Not. Mitchelli by the greater breadth or thickness of the postbasal 

 ridge. 



