ELEPHAS PRIMIGENIUS.— TRUE MOLARS. 123 



more detrited than the preceding, having lost a few more plates, and the heel is level with 

 the anterior border. There is no rostrum, only a slight beak, with the borders of the 

 diasteme running down to a point in front of the chin, to meet and form the chevron- 

 shaped front shown in the Woodcut, fig. 7 (p. 135). 



The molars from the Arctic regions, although very characteristic on account of the 

 extreme tenuity of their enamel, exhibit exceptional instances, which, with similar 

 cases from British and European localities, seem to me to point to the thick- and thin- 

 plated teeth as being often casual differences and individual peculiarities. A mandible 

 in the British Museum, from Eschscholtz Bay, a front and profile view of which are 

 shown in Woodcut, fig. 5 (p. 135), is referred to by Buckland in the Appendix to Beechy's 

 ' Voyage of the Blossom.' It has lost a portion of the right ramus, and both of the 

 coronoid processes, otherwise the jaw is entire. This mandible is typical of the Arctic 

 specimens. The dental canal is large, gaping, and opens directly upwards, with a small 

 projecting spine on its anterior border. The condyle and its neck viewed from behind 

 show a pronounced concavity on the inner border of the latter, but it is not so deep as 

 in the Asiatic, yet it has the prominent crotchet which seems very general in the Asiatic 

 as pointed out by Busk, and considered by him to be characteristic of that species.-^ 

 The height in front of the molar is 6^ inches, and maximum width of the ascending ramus 

 at the base of the coronoid is C^ inches. The front portions of the teeth are ground down, 

 leaving thirteen plates Avith a projecting heel in 8^X 3j inches, whilst eight plates occupy 

 a space of 4^ inches. The plates here are tkicJc, and the machserides crimped, such as are 

 not common in Siberian and North- American molars. The breadth in front between 

 the teeth is 2j inches, at the middle 5 inches, and posteriorly 1\ inches. The elevated and 

 rounded heel is just half an inch behind the anterior border of the coronoid, yet the part 

 of the ascending ramus behind is made up of spongy and cancellated bone without any 

 appearance of plates. This must have been a very old Elephant. 



There is another mandible of Siberian origin in the British Museum, holding two well- 

 worn ultimate true molars ; the rounded heel, however, is 3 inches behind the anterior 

 border of the coronoid, and quite flattened, as in the preceding, with a space^ of 

 7 inches between it and the entrance to the dental canal. Mr. Davies caused, as in the 

 preceding, an incision to be made in the back portion of the ascending ramus, but 

 without meeting with a trace of a colline, and only the spongy septum present, made up 



1 ' Trans. Zool. Soc. London,' vol. vi, p. 237. 



2 The position of the heel of the molar in wear with reference to the anterior border of the coronoid 

 will readily indicate to the student the state of advancement he may expect of the successional tooth, as 

 shown by numerous beautiful examples in the rich and instructive collection of the Royal College of 

 Surgeons. In a nearly similar instance to the above in the Asiatic Elephant the second true molar 

 has thirteen of its anterior ridges invaded, and heel two inches behind the anterior border of the coronoid, 

 whilst the vault of the third molar is just broken through, and the coUines are lying loose in their 

 capsule. See also the mandible of the Mammoth with the first true molar in full wear in the ' F. A. 

 Siv.,' pi. xiii A, fig. 2, and that of E. Hysudricus, fig. 7. 



