EAICONEE MASTODON AND ELEPHANT. 275. 



ruptly pronounced. The ivory surface is deeply excavated, so that 

 the enamel edge projects in high relief above it. The fifth and 

 sixth disks are of a similar form, but, being less worn, they are less 

 expanded. Their cornua are bent forwards on the inner side, with 

 the crescentic character seen in the fourth, fifth, and sixth disks of 

 the Gray's Thurrock specimen. The anterior enamel plate of the 

 sixth disk projects very much (to the extent of seven-tenths of an 

 inch) above the contiguous stratum of cement, while the included 

 ivory surface is but slightly depressed. The seventh, eighth, and 

 ninth disks present a corresponding form, getting narrower succes- 

 sively in consequence of being less worn, but each showing more or 

 less of a mesial angular expansion. The tenth ridge is but slightly 

 worn, and the disk is barely continuous across. The eleventh and 

 twelfth ridges show each two distinct disks. The posterior talon 

 shows the tips of two denticles or digitations, like the last ridge of 

 the Gray's Thurrock specimen. To the posterior surface of the last 

 there is appended a single thick digitation, which projects backwards 

 in a salient gibbosity, being the converse of what is seen in the re- 

 entering sinus, on the posterior surface of that specimen. 



The grinding-surface is very concave from back to front, a chord 

 stretched from the front to the last ridge being fully 1-4 inch above 

 the level of the sixth and seventh disks. It is also a good deal con- 

 torted, the anterior inner side sloping backwards and outwards, 

 while the posterior outer angle slopes forwards and inwards, corre- 

 sponding precisely in this respect with the specimen of the last lower 

 molar of E. (Euelephas) Hysudricus, represented by fig. 13 o, pi. 12 

 of the ' Fauna Antiqua Sivalensis.' 



The enamel plates are very thick ; and their outer edges present 

 an appearance of crimping, caused by the deep vertical grooving of 

 the outer surface, namely that in contact with the stratum of 

 cement ; but they are not plaited. 



The principal dimensions are as follows — 



inches. 



Length of crown about 12 



Width of crown at fourth ridge 3*1 



„ „ sixth ,, 3'35 



„ „ eighth „ 3-4 



,, „ tenth „ 3-1 



„ „ twelfth „ 2-6 



Width of posterior talon 1"65 



Height of crown at fourth ridge (much worn) . . 1-6 



„ „ sixth ,, outer side 3*1 



„ „ ninth „ „ 4-5 



„ „ twelfth „ „ 5-2 



Mesial expansion of fourth disk 0*75 



The crown includes twelve ridges in a length of about 12 inches, 

 being an average of one inch to each. The specimen was compared 

 with an exact drawing, of the natural size, of the Gray's Thiirrock 

 molar ; and the two agreed in the closest manner, making allowance ' 

 for their different stages of wear. This very important specimen 



