286 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



a young lower jaw of the same age as the fragment comprising the 

 corresponding upper teeth. The two fragments are considered by 

 the authorities of the Museum to be upper and lower of the 

 same individual, and they agree exactly in their mineral condition 

 and appearance. On the right side, the antepenultimate is want- 

 ing ; on the left, it exhibits a well-worn crown, composed of three 

 principal ridges with front and back talons. It is much smaller 

 and more compressed in front than the upper tooth, and in the 

 general form it is somewhat cusp-shaped, Hke the corresponding- 

 tooth of the Sewahk E. {Loxod. ) planifrons. 



The penultimate (or second) inferior milk-molar presents six 

 principal ridges, besides a front and back talon ; the three anterior 

 ones more or less worn, the next intact. Making allowance for 

 the difference of upper and loAver, the tooth is exactly like the cor- 

 responding penultimate above. The plates are thick, and the 

 ridges wide apart, the valhcular intervals being but imperfectly 

 covered with cement. On the right side, there are about six loose 

 unconsolidated plates of the third milk-molar in the alveolar cavity ; 

 on the left side, only the empty alveolus. The principal dimensions 

 of the specimen are — j , 



United length of the two milk molars 3-0 



Length of the fii'st 0-7 



Length of the second 2-4 



Width of ditto at first ridge 0-8 



Interval between the anterior edges of the two milk 



molars 1-7 



The last milk-molar is beautifully preserved in an older jaw, 

 although still young, comprising the right ramus, with the remains 

 of the second milk-molar in front, and the empty alveolus of the 

 antepenultimate true molar behind. The age of the interposed 

 third milk-molar is therefore very pointedly indicated. The crown 

 presents eight principal ridges, with front and back talons. The 

 four anterior ridges alone are affected by wear, — the first shoAving 

 two distinct, curved and reniform disks, with the convexity in 

 front; the second, three continuous but separate disks; the third, 

 four; the fourth barely abraded, but exhibiting the rings of five 

 digitations. The tooth, in its longitudinal direction, has the usual 

 curve, being concave on the outer side. The ridges are wide apart, 

 and enwrapped by an enormous layer of cement, very much as in 

 the young teeth of E. {Loxod.) planifrons. In its general form, 

 the crown differs notably from the second milk-molar, in presenting 

 a nearly uniform width from front to rear. There is no indication 

 of plication in the enamel of the plates, nor any outlying mesial 

 loops. The specimen is hard and heavy, resembling in its mineral 

 condition the hard Sewalik fossils when a little weathered. The 

 dimensions of the tooth are — Inches 



Length of crown 4-6 



"Width of ditto at first ridge 1-6 



Width of ditto at fifth ridge 1-8 



