310 



cuous in the fore and back part of the coronal eminences than upon their 

 outer and inner side. The outer border of the transverse eminences is 

 more convex than the inner one. The course of the calcigerous tubes is 

 unusually clear upon the broken surface of the fang. 



From the alluvial or newer tertiary deposits in the district of Mel- 

 bourne, Australia. Presented by Dr. Hobson. 



1494. The third or antepenultimate molar, left side, lower jaw, wanting the 



anterior fang, of the same individual Diprotodon australis. Like the 

 preceding tooth it shows that it belonged to an older, and likewise to a 

 rather larger individual than No. 1492 : the crown has been more worn, 

 and shows better the depth of the interspace between the two principal 

 ridges, the slight production of the middle of the posterior surface of 

 the anterior ridge, and the depression on the opposite surface of the pos- 

 terior ridge. The antero-posterior extent of the base of the crown of 

 this tooth is one inch nine lines ; the breadth of the crown is one inch 

 three lines ; the height of the crown is one inch two lines ; the length of 

 the posterior fang was two inches when entire. 



From the alluvial or newer tertiary deposits in the district of Mel- 

 bourne, Australia. Presented by Dr. Hobson. 



1495. The crown of the penultimate molar, left side, lower jaw, of apparently 



the same individual Diprotodon australis. The anterior transverse ridge 

 had just begun to be worn : the summit of the posterior ridge is entire. 

 This is not divided into small mammilloid tubercles as in the Dinotherium, 

 but is irregularly and minutely wrinkled as in the Tapir. In the depth of 

 the cleft between the two transverse ridges, the teeth of the Diprotodon 

 resemble those of the Tapir more than those of the Kangaroo ; but the 

 eminences are higher and more compressed than in either of the existing 

 genera cited. In the largest existing species of Kangaroo, as the Ma- 

 cropus major and Macr. laniger, the lower molars have no posterior talon 

 or basal ridge ; but this is present in the still larger extinct species called 

 Macropus Atlas, in which, however, it is much smaller than the anterior 

 talon. In the Tapir the anterior talon is also larger than the posterior 

 one, but in the Diprotodon the proportions of the two basal ridges are 



