FALCONER MASTODON AND ELEPHANT. 327 



crown of the penultimate lower milk-molar perscnts eight ridges, 

 besides talons. 



Of the last milk-molar of the lower jaw (third in the order of 

 appearance) a very fine example m situ is afforded by a cast of a 

 mandible, in the Museum of the College of Surgeons. Both rami 

 are complete, with the exception of the articular surfaces of the 

 condyles. The last milk-molar, well worn but perfect, is present 

 on either side, with the empty sockets of the penultimate in front 

 and of the first true molar behind. 



The dimensions of the last milk- molar, left side, are — 



inches. 



Length of crown 3'9 



Width in front 1-2 



Greatest width behind 1*7 



The crown is composed of twelve ridges, with talons closely approxi- 

 mated. The original of this specimen is reputed to have been 

 found in the superficial deposits of the valley of the Ehine. 



Another example of the last milk-molar of the lower jaw, de- 

 tached, may be cited in the specimen in the collection of the British 

 Museum, no. 21,315, from Ilford, Essex. The crown is composed 

 of twelve principal ridges, with talons, the anterior six being worn, 

 and the rest intact ; the ridges are closely approximated, and the 

 disks of wear form parallel transverse bands, with no tendency to 

 expansion in the middle, and with the plates of enamel attenuated 

 and free from crimping. 



The dimensions are — inches. 



Length of crown 3'7 



"Width of crown in front ] ■ 1 



Greatest width, behind 1-5 



Height at the seventh ridge 2-3 



Numerous other examples might be cited ; but these two suflflce to 

 indicate the ordinary characters of the tooth. 



The third milk-molars in the Mammoth, upper and lower, are 

 distinguishable with facility from those of E. (Loxod.) meridionalis 

 and from E. {EuelejjJi.) antiquus by the duodenary cipher regulat- 

 ing the crown-ridges, and by the tenuity of the enamel plates ; but 

 the antepenultimate and penultimate are much less easily dis- 

 criminated. 



Taking the numbers yielded by the examples above given, it is 

 seen that the ridge-formula of the milk-molars in E. prlmigenms is 

 identical with that of the existing Indian Elephant, and liable to 

 the same variation as regards the antepenultimate, upper and lower, 

 as is met with in that species, namely, the ridges varying from 



A I Sj I "I O 



seven to eight. The formula may be expressed thus : — . ^ . 

 ^ _ •' ^ 4-1-8-^-12 



exhibiting a progression by successive increments of four. 



c. Upper true Molars. — The creiumstances which render it diffi- 

 cult to determine with precision the ridge-formula of the true molars 

 in the existing Asiatic form apply equally to those of the Mammoth ; 



