98 BRITISH FOSSIL ELEPHANTS. 



The dimension of this tooth varies considerably. In upper molars the antero- 

 posterior measurement is as low as 3^ inches and the maximum 5^ inches, whilst the 

 breadth varies from 1'4 to 2-5 inches. 



The lower molar does not appear to exceed the maximum length of the upper, but I 

 have not seen one of the former so low as 3" 9 inches in length. Its width is seemingly 

 the same as in the upper. Sometimes molars of this, as in succeeding teeth, show, 

 especially in the mandible, a tendency to arcuation, which, however, as a rule, is not 

 general in the Mammoth. 



Affinities. — The ridge formula of this member of the series in T^. primigenius and 

 jS'. Asiaticus are precisely alike, ranging from nine to twelve plates besides talons. In 

 E. antiquus and I]. NamacUcus the numbers extend from nine to eleven plates, whilst in 

 U. meridionalis it seldom exceeds eight plates ; the same, seemingly, and even a lower 

 number, obtaining in E. Africanus, E. Hysudricus (?), and E. bombifrons. 



The only species with which the ultimate milk molar of the Mammoth is likely to be 

 confounded is that of the E. ^antiquus. Ordinarily, the higher expression of the ridge 

 formula and disks will distinguish the former when the crown is well worn ; but some- 

 times, should the wearing down be not pronounced and the number of plates come 

 within the range of that of the Mammoth, the diagnosis might be uncertain. As to the 

 differentiations from the last milk molars of other species, I need not repeat what are 

 detailed at length in my Monograph on E. antiquus, p. 20. 



Like its predecessor, the last of the milk molars is plentiful in collections from the 

 brickfields east of London, and, whether through accident, disease, or attacks of enemies, 

 the Mammoth did not attain to old age without running many risks, and this is further 

 shown by the undiminished numbers of last milk teeth from bone caverns throughout 

 England. It has also been recovered from the bed of the German Ocean, and 

 represents the most youthful examples of its owner hitherto recorded from Ireland. 



3. TRUE MOLARS. 



The Ante-penultimate or First True Molar. 



» 

 A small first true molar may be easily mistaken for a large ultimate milk molar, and 

 the latter for a small first ; indeed, the chances of such deceptions are the lot of the most 

 experienced manipulators of Proboscidean teeth. The only certainty occurs cither when 

 the molar is found in the jaw or when the larger size indicates dimensions beyond what 

 usually obtains in last milk teeth. 



The rapid growth of the living species of Asia, whose life-history is best known, makes 

 greatest progress between the decadence of the penultimate milk and the commencement 



