167 



maining eminences present three, four, or five mammillae ; those of the 

 hindermost division being arranged in an oval form. 



From the tertiary deposits of the left bank of the Irawadi, Ava. 



Presented by the Geological Society of London. 



687. A plaster cast of part of the upper molar tooth of the right side of the 

 Mastodon latidens. 



From the tertiary deposits of the left bank of the Irawadi, Ava. 



Presented by the Geological Society of London. 



688. A plaster cast of part of the right ramus of the lower jaw of the Mastodon 



latidens. The grinding surface, which is nine inches in length, presents 

 six transverse eminences ; the first two have been blended together by 

 attrition, the third is worn to a continuous transverse depression, the 

 fourth and fifth are each divided into two equal mammillary eminences, 

 the sixth terminates by four obtuse mammillae, three in the same trans- 

 verse line and the fourth behind. 



From the tertiary strata on the left bank of the Irawadi, Ava. 



Presented by the Geological Society of London. 



689. A fragment of a larger molar tooth of the Mastodon latidens, presenting 



two unworn ridges, one divided into four, the other into three obtuse 

 mammillae. 



From the tertiary strata near the left bank of the Irawadi, Ava. 



Presented by the Geological Society of London. 



Mastodon angustidens. 



690. A fragment including the middle part of the left ramus of the lower jaw 



of the Mastodon angustidens, Cuv. [Mast. Sivalensis, Cautley). It 

 exhibits the crown of an entire grinder, apparently the penultimate one, 

 and a small portion of the succeeding grinder : the penultimate grinder 

 supports five transverse ridges, the first four being divided into two 

 principal mammillae directed obliquely and alternately, with their internal 

 angles wedged into the opposite interspaces ; the first transverse ridge 

 has been preceded by a narrow talon ; the posterior and smallest ridge is 



