114 FAUNA ANTIQUA SIVALENSIS. 



bisecting the tooth, as in the true Mastodons, into an outer and inner 

 division. The ridges are a little convex in front and concave behind, 

 determining a similar form to the valleys between them, which run 

 across without interruption, there being no accessory mammillEe deve- 

 loped so as to encroach upon the valleys. The mammilla are obtuse 

 and closely packed ; they are obscurely separated from each other by 

 shallow grooves or fissures, and nine or ten of them may be counted on 

 the intact ridges. Hardly any crusta petrosa is visible except between 

 the 5th, 6th and 7th ridges. The ivory is very thick, with a rugose 

 surface very much like that of Mastodon latidens. Overlapping the 

 front ridge there is a small portion of the ivory of the penultimate 

 molar, the remains of which had not yet dropped out. 



Dimensions. 



Inches 



Extreme lengtli of crown of molar ...... 9'35 



Breadth of ditto at second ridge ....... 4-3 



Ditto at fifth ridge 4-05 



Ditto at seventh ridge , . . . . . . . 3'6 



Ditto of heel 2-8 



Height of crown of third ridge, taken at outside . . . 1'3 



Ditto at inner .......... 1" 



Two large fangs are visible on either side in front, and another out- 

 side below the third ridge. 



The cro^vn of the tooth tapers gradually and slightly from in front 

 backwards. 



The ridges of enamel, even where intact, are very low for the size of 

 the tooth. 



Inches 

 Extreme length of specimen is . . . . . . . 13- 



Height of ditto from surface of fifth ridge to fracture ... 8" 



The characters of the crown of the tooth agree very closely in every 

 respect with the tooth of the lower jaw figured in Faun. Anticj. Siv. 

 PI. XXX. fig. 5, and it is inferred to be the last true molar of the upper 

 jaw, represented in fig. 3 of that plate. It is possible that the fragment 

 in fi'ont which is attribvited above to the penultimate molar may be an 

 anterior ridge of the last true molar which had got detached from 

 wearing out, in which the normal character of the tooth woidd be to 

 have eight ridges and a talon instead of seven as described above. 

 Supposed to be one of the seven jaws mentioned in the Journ. As. Soc. 

 vol. iii. p. 365. 



No. 16. Elephas Cliftii. — Fine fragment, comprising the horizontal 

 ramiis lower jaw, left side, with nearly the whole length of the last molar 

 embedded in it ; broken oiF in front at the symphysis showing a part 

 of the diastemal ridge, and behind, a little in front of the offset of the 

 coronoid, the fractiure vertically including a portion of the fang ; a 

 single mental foramen is shown in front of considerable size. The 

 whole of the anterior two-thirds of the crown of tlie molar is entirely 

 worn out into a hollow surface of ivory without any enamel. The ivory 

 is seen to be of great thickness. Two ridges and a part of a third are 

 seen behind, the front one well worn, the last barely touched. An 

 intact mammilla is seen bounding each of the rear valleys at the out- 

 side, and a considerable quantity of crusta petrosa fills up the valleys. 

 There is no indication of a longitudinal bisecting line along the crown. 



