120 FAUNA ANTIQUA SIVALENSIS. 



No. 3. Mastodon latidens ? — Specimen consisting of the horizontal 

 ramus of lower jaw left side, trmicated obliquely downwards and back- 

 wards in front of the molar and behind about the middle of the ascend- 

 ing ramus, of which it shows a part. The specimen is dark-coloured 

 from ferruginous infiltration and is sparingly covered with a thin crust 

 of gritty calcareo-arenaceous matrix, resembling that found on the sur- 

 face of many of the Ava fossils. The whole length of the molar tooth 

 is visible in siht, but unfortunately all the enamel surface of the crown 

 is broken off, so as to deprive us of any direct and conclusive evidence 

 as to the species, but it is evident that the tooth is the third or last tj-ue 

 molar, as the section behind shows no marks of the nucleus of another 

 successional tooth to come after it ; but from the narrowness of the 

 cro^vn, it is confidently inferred that the specimen belonged to a true 

 Tetralophodon mastodon (either M. latidens or M. Perimensis^ and not 

 to E. [Stegodon) Cliftii. The jaw is characterized by its great transverse 

 diameter behind and great height in front. The removal of the sym- 

 pliysis has carried away the outer orifices of the mental foramina, but 

 two canals are seen in the section which also exhibits a nearly cylindrical 

 core, which is probably the residuum of the fang of a shed molar or a 

 tusk of the lower jaw ? 



Dimensions. 



Inches 

 Extreme length of fragment from broken edge vid sympliysis to 



broken edge behind ......... 16'7 



Height of jaw measured outside immediately in front of molar . 8'5 



Ditto ditto behind 67 



Greatest diameter behind, taken at bulge of ascending ramus . . 8* 



Diameter in front in a vertical line with the anterior edge of the 



molar ............ 5'4 



Extreme length of alveolus and crown of molar .... 10' 



Diameter of crown of molar in front ...... 2-4 



Ditto where widest behind ,.....,, 2-8 



The tooth narrows very much from behind backwards, as seen in the 

 section ; the residuary portion of the crown of the molar vicAved from 

 the inside in front is elevated 1 to 6 inches above the alveolar border. 

 There is no portion of the enamel visible except an edging on the 

 outer side. 



The form of the lower jaw is much thicker and shorter in proportion 

 than in the existing Indian elephant, further supporting the conclu- 

 sion that it belongs to a true mastodon. 



This is a valuable and characteristic specimen ; and it is much to be 

 regretted that there is no tracing its origin in the records of the Asiatic 

 Society. Is it one of Col. Burney's specimens from Ava ? 



No. 4. Mastodon latidens. — Fragment of lower jaw left side, com- 

 prising part of horizontal ramus from base of coronoid apophysis to 

 about 6^ inches forward, containing the posterior half of a well- 

 preserved molar, which is inferred to be the last or third true molar 

 from the absence of the indication of any other forming behind. It 

 shows four ridges with a talon, the three anterior of which are well 

 worn, showing that the animal was fully adult. The tooth agrees in 

 the closest manner in size, form, amount of wear and every other 

 respect with the corresponding specimen figured in Faun. Ant. Siv. 

 PI. XXX. fig. 6, which, however, has a ridge more in front preserved. 



