162 



fang, and the posterior large-grooved conical fang of the grinder in use, 

 are exposed. 



From the tertiary formations of the Sub-Himalayan district, India. 



Purchased. 

 665. The right ramus of the lower jaw of the Mastodon elephantoides, with 

 the symphysial extremity and the coronoid and condyloid processes 

 broken off; in the first molar the grinding surface is five inches in 

 antero-posterior extent, and presents five transverse ridges, the abraded 

 depressions of which are slightly wider at the middle than at the outer 

 and inner extremities ; the thick enameled ridges with which they are sur- 

 rounded are plicated ; of the second molar tooth eight of the transverse 

 ridges have emerged from the socket, but only the first four have begun 

 to be abraded, and in not any of them are the numerous mammillary 

 eminences entirely worn away. Compared with the lower jaw of the 

 African Elephant, the antero-posterior extent of the ascending ramus in 

 the Elephantoid Mastodon is much greater than that of the molar series 

 anterior to it ; the depression on the outer surface of the ascending 

 ramus is greater, and the convex prominence of the bone below it is 

 broader and more horizontal ; the ridge which extends from the anterior 

 part of the molar series downwards to the symphysis is broader and more 

 obtuse in the Mastodon ; the lower convex surface of the ramus is like- 

 wise considerably broader, but the general resemblance with the lower 

 jaw of the Elephant is much greater in this species of Mastodon than in 

 the Mastodon giganteus. From the Mastodon giganteus the Mastodon 

 elephantoides differs in the rounding off of the angle of the jaw, in the 

 diminished length of the horizontal ramus, in the greater depth of that 

 part anterior to the first molar, and in the much smaller concavity on the 

 inner side of the ramus ; the circumference of the ramus anterior to the 

 coronoid process is twenty-two inches in the Mastodon elephantoides 

 and nineteen inches in the 3tastodo?i giganteus ; the length of the jaw 

 in the Mastodon elephantoides being twenty-seven inches, and that of 

 the Mastodon giganteus compared with it being twenty-four inches. 

 From the tertiary formations of the Sub-Himalayan district of India. 



Purchased. 





