Tertiartj.-] PALiEONTOLOGY OF VICTORIA. \_Mammalia. 



of tlie molars {m. 2, d. 3) (not marked in D. Ausfralis), and 

 in the miicli smaller development of the basal ridges. 



The middle incisor of the upper jaw (/. 1) figured on our Plate 

 XXXIII., fig. 2, from the Pliocene clays of Back Creek, may belong 

 to this species ; but of this I cannot be certain. It differs from the 

 corresponding tooth of D. A ustralis in being flatter : the sub-trigonal 

 section, taking the longest transverse diameter as 100, gives a 

 proportion thereto for the greatest diameter of the thicker side 

 amounting to about y^V •" tli6 present tooth, and upwards of yV"o 

 in the corresponding part of D. Ausf rails. 



The fine specimen of the lower jaws figured was obtained in 

 sinking a well in the Pliocene clays of Colac. It has the molar 

 series of each side of the lower jaw perfect and in ])lace, with the 

 two great tusks also perfect and in their sockets. The individual 

 was an aged one, as shown by all the molar teeth being worn by 

 attrition against those of the upper jaw, and by the first molar 

 (d. 3) not only having been long shed, but its sockets so completely 

 filled up with bone as scarcely to leave a trace of their existence. 



A very important specimen included in the hard fresh-water 

 Pliocene Tertiary limestone of Liineburner's Point, near Geeloug 

 (45 miles S.W. of Melbourne), presented to the Museum by 

 Mr. Mercer and Dr. Day of Geelong, shows the two rows of molax's 

 of the upper jaw in place, but the crowns are all broken off ; the 

 bony palate is only 3 inches 7 lines wide opposite the interval 

 between the last and penultimate molars ; or 1 inch less than the 

 corresponding part of the D. Australis. Being broken behind 

 this line I cannot say where the post-palatal vacuities may have 

 reached to. 



Explanation of Figures. 



Plates XXXr. and XXXII. — Fig. 1, one ramns of lower jaw, viewed from the upper and 

 inner side, with tlie three molars and last decMnous molar in situ, and with a small projection 

 in front of the latter, possibly indicating the socket of a preceding tooth. The anterior portion 

 of this specimen (which is only half the original) shows the undivided anterior portion of the 

 mandible with the exposed portions of the two great incisor tusks characteristic of the 

 genus. }Ia!t the natural size. Fig. \a, external view of same specimen, half tlie natural size. 

 Fig. li, crown of last molar, natural size, showing the reticulo-pnuctate en.iniclled surface. 

 Fig. Ic, one of the incisor tusks, natural size. Fig. 1'/, section of ditto at point of emergence 

 from the snckct. Fig. 2, lower tusk of Nototlieriitm from Back Creek, inner side, natural size. 

 Fig. 2rt, ditto outer side, showing the rugged enamel. Fig. 2A, portion of surface, magnified to 

 show the wrinkled and punctate eh.aracter of the surface enamel, magnified. 



I'late XXXIII. — Kig. 1, three molars and last deciduous molar of same specimen of D. 

 longiccps, natur.al size. — (All the aliove from Colac.) Fig. 2, front view, natural size, of portion 

 of anterior incisor of upper jaw of a Uiprotodon from Back Creek, imperfect at each end. 

 Fig. 2a, side view of ditto, natural size. Fig. 2A, transverse section of ditto, natural size. 



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