. On the Fossil Mammals of Australia. Part III. Diprotodon australis, Owen . e of tooth. The fore-and-aft extent of the socket is 9 lines, that of the hindfossa or division is 3^ lines, that of the front one 2^ lines, and that of the interveningbar is 2^ lines at its prominent part. In the younger jaw the second molar (Plate XLI. figs. 1 & 2, d 4) has both lobes ofthe crown about half worn down; the fore-and-aft extent of the crown, including theanterior and posterior basal ridges, is 1 inch 6 lines. The anterior basal ridge is thickestat its outer part, and here the enamel has been worn ofi*


. On the Fossil Mammals of Australia. Part III. Diprotodon australis, Owen . e of tooth. The fore-and-aft extent of the socket is 9 lines, that of the hindfossa or division is 3^ lines, that of the front one 2^ lines, and that of the interveningbar is 2^ lines at its prominent part. In the younger jaw the second molar (Plate XLI. figs. 1 & 2, d 4) has both lobes ofthe crown about half worn down; the fore-and-aft extent of the crown, including theanterior and posterior basal ridges, is 1 inch 6 lines. The anterior basal ridge is thickestat its outer part, and here the enamel has been worn ofi* in mastication. The flat foreside of the front lobe rises 5 lines above the ridge. The abraded surface (Plate 3, a) of this lobe is 8 lines in transverse and 4 lines in antero-posterior extent, themid part being increased in this direction by an outswelling of the hind surface there ofthe lobe. The outswelling of the front slope or surface of the hind lobe is situated moreoutwardly: the abraded surface (Plate XL. fig. 3, b) of this lobe is narrower from before. PEOFESSOE OWEN ON THE FOSSIL MAMMALS OF ATJSTEALIA. 536 backward, broader transversely, than that of the front lobe. A low and short ridge ofenamel Qi) closes both outer and inner ends of the intervening transverse valley. Thelength or vertical extent of crown between the end of the valley and the division intofangs is 5 lines on the inner side and 4 lines on the outer side of the tooth. The middleof the hind surface of the hind lobe swells out; and as both outer and inner ends of thehind basal ridge {g) bend up the corresponding parts of the hind lobe, its hind surfaceshows two shallow depressions divided by the above-named rising: in these depressionsthe reticulo-punctate character of the enamel is most strongly marked. The hind basalridge is thicker than the front one (/), and thickest at its middle; its enamelled marginis irregular, it rises higher than, and seems to overlap, the front basal ridge of the foLl


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Keywords: ., bookcentury1800, bookdecade1870, bookidphiltrans096, bookyear1870