163 



666. A plaster cast of a considerable portion of the left ramus of the lower jaw 



of the Mastodon elephantoides, with the socket of a worn-out molar, and 

 the entire crown of the succeeding molar displayed. Of this tooth only the 

 two anterior divisions of the crown have come into use, and of these the 

 tips of four of the mammillary terminations of the second plate are alone 

 abraded ; the summits of the succeeding transverse conical eminences 

 are terminated by five or six small and nearly equal conical obtuse mam- 

 millae. The length of the tooth is twelve inches, the number of transverse 

 mammillated eminences is ten inches. 



See the Geological Transactions, Second Series, vol. 2. Part III. 



Presented by the Geological Society of London. 



667. Part of the left ramus of the lower jaw of the Mastodon elephantoides, 

 containing two molar teeth : the grinding surface of the first is six inches 

 in length, and presents eight transverse ridges ; of the second molar the 

 mammillated summits of five ridges have emerged from the sockets, but 

 none of these have been abraded by mastication ; the direction of the 

 fibres of the thick enamel on the posterior fractured surface of this tooth 

 is well shown. 



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



Purchased. 



668. A portion of the left ramus of the lower jaw of the Mastodon elephan- 



toides, containing a considerable proportion of a molar tooth : the grind- 

 ing surface shows seven transverse ridges, the mammillary summits of 

 which are worn away in the first two, and more or less abraded in the 

 two following. The pulp-cavity and fang are exposed at the anterior 

 end, and the direction of the fibres of the thick enamel is well displayed 

 at the posterior fractured surface of the tooth. 



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



Presented by the Rev. E. Everest, F.G.S. 



669. A considerable part of the right ramus of the lower jaw of a young Mas- 



todon elephantoides. with two molar teeth : the crown of the first is 

 divided into seven transverse ridges, the first and second of which are 

 worn down to the common base of dentine, and from the others, with 



y 2 



