26G 



third molar (m 1) than in the three preceding specimens. Nevertheless I cannot feel 

 that 1 have grounds for propounding any distinction of specific value for the Notothere 

 yielding the present fossil. The fracture through the hind part of the symphysis 

 exemplifies the complete bony confluence of this part, and the non-existence therein of 

 the wide alveolus of a large scalpriform tusk. The transverse fracture anterior thereto 

 ut the interval between the first and second molars exposes the dental canal, of 4 lines 

 diameter, situated 2 inches below the outlet of the socket, and 1| inch above the lower 

 surface of the symphysis. 



The fifth mandibular specimen of Nototherium Mitchelli is from the freshwater beds 

 traversed by Gowric Creek, Darling Downs; it was there collected by Henry Hughes, 

 Esq., by whom it was presented to the Natural-History Society of Worcester. This 

 specimen is chiefly valuable for the more perfect and less worn condition of certain of 

 the molar teeth. It consists of a right ramus mutilated (as most of these fossils from 

 river-beds are) at both ends. The relative position of the back part of the symphysis 

 and of the entry of the dental canal, with the general size and proportions of the best 

 preserved parts of the ramus, show the specimen to have belonged to the Nototherium 

 Mitchell/'; and it agrees most closely with the more perfect mandible in the Australian 

 Museum at Sydney, which I have referred to the female of that species. 



The subject of Plate XL. is an instructive specimen of a mandibular ramus and den. 

 tition of a young Notothere; it was transmitted to me, in 1847, by the enterprising 

 and unfortunate explorer of Australia, Ludwig Leichhardt, to whom I had been pre- 

 viously indebted for the account of the geology of the locality yielding this and other 

 remains of extinct Marsupials (p. 241). 



I incline to refer this specimen, from the size of the incisor and of the three anterior 

 molars, to Nototherium Mitchelli. The generic indications in the present fossil will be 

 noted in § 4, on the teeth of Nototherium: the characters of the bone exemplify mainly 

 those of immaturity. It consists of a right ramus, which, being figured of the natural 

 size in Plate XL., precludes the need of noting dimensions. The antero-posterior extent 

 of the three anterior molar-sockets will be seen to agree with that in the mature man- 

 dible, Plate XXXIX. 



The ascending ramus has been broken away, exposing the formative alveolus of the 

 penultimate molar (figs. 3 & 4, m 2) and the like cavity at an earlier stage of the last 

 molar (ib. m 3). Provision has been made in this cavity for the lodgment of the anterior 

 lobe of a tooth of equal transverse diameter (14 lines) with that of the tooth (m 3) 

 in place and use in the largest examples of the present species. The dental canal 

 (fig. 3, 0) exposed by the hinder fracture presents a semielliptic form, 9 lines transversly 

 and 3 lines from before backward. The canal undermines, as it were, the shell of the 

 last formative alveolus, and it contracts as it inclines toward the outer wall of the ramus 

 in its forward course. 



The contour of the lower border of the ramus from the hind fracture to the symphysis 

 (Plate XL. figs. 1 & 4, e, s!) is a more open curve than in the adult; it is feebly inter- 



