﻿ELEPHAS ANTIQUUS — TRUE MOLARS. 



27 



Second True Molar. 



It will be apparent from the foregoing that long first true molars with the maximum 

 number of ridges (14), more especially mandibular specimens, are apt to be confounded 

 with unusually small second true molars. It is of assistance however to the observer 

 to bear in mind that the graduating height of the ridges posteriorly as characteristic of 

 the last of the series is also pronounced in second molars, especially in the lower jaw, 

 and even in the first true molar ; whilst the pressure scar on the heel of such worn teeth 

 precludes the possibility of confounding the penultimate with the ultimate true molar. 



The question is frequently suggested during surveys of detached molars of Elephants, 

 When is the pressure scar developed on the disappearing tooth ? It seems that certain 

 members of the dental series are pushed forward more rapidly than others. Eor example, 

 the first or antepenultimate milk tooth is soon shed, and the last milk and first true 

 molars take on the pressure scar and impressions of the advancing septum sooner than 

 the penultimate milk and penultimate true molars. At all events, the scar and septal 

 pressure hollow or flattening below the posterior talon, and on the posterior fang, in both * 

 upper and lower molars become pronounced long before the crown is worn out ; whereas 

 in lower molars it is often observed that the last ridges are being ground down before 

 the succeeding molar has made an impression on the heel of its predecessor, There are 

 doubtless individual differences, according to the quickness or otherwise of the growth of 

 the animal, when the teeth advance with greater or less rapidity. Perhaps the greatest 

 strides in the growth of the Elephant take place at the age when the last milk and first 

 true molars are being ground down, the full vigour not being attained until the second 

 true molars come into wear, when the epiphyses of the long bones get consolidated. 

 It may therefore be the case, that the intermediate molars advance with greater rapidity 

 than the succeeding teeth. At the same time I have been informed by a German 

 dealer, who has reared Elephants in the forests of Upper Burmah, that the animal's growth 

 as regards height is pretty steady and about six inches annually. 



An upper molar denuded of its external cement and unworn, No. ^'J^' B. M., is 

 from fluviatile deposits at Slade Green, Erith ; a profile view of this tooth, half natural 

 size, is shown in Plate II, fig. 1. It displays fifteen ridges, or x 13 a? in a space of 

 10*5 inches. The narrowness of the crown, the height of the collines, the seventh 

 being 6*3 inches, the ribbing and rugte of the enamel, and thickness of plates, are 

 characteristic of this Elephant. A beautiful plan view {natural size) of another second true 

 molar is represented in Plate IV, fig. 2. The tooth is from Grays, Essex, and is one 

 of two upper molars, right and left, No. 22,017, B. M., of probably the same individual. 

 Like the above, it is typical as regards the long narrow crown, and is somewhat bent. 

 It holds x 12 x in 9 inches. The crown, narrow in front, expands towards the middle, 

 and again narrows posteriorly. 



