ELEPHANT AND MASTODON. 



79 



least vertical space. The basal mass of ivory between the 

 plates and the fangs is reduced to a small quantity. This 

 tooth measures 15^ inches long in a straight line.' 



rig. 3, PL V. (or fig. 1, PI. I., r.A.S.), represents a section 

 of the last iTpper molar of E. primigenius, from an English 

 specimen in the Museum of the Geological Society, found 

 near Kingsland. We arrive here at the last link in the 

 chain of modifications, exhibited by the molar of the typical 

 elephants. The section bears a close resemblance to that of 

 the corresponding tooth of the Indian elephant, but the 

 ivory segments are more vertical, thinner, and more approxi- 

 mated, there being about twenty-two plates in the space 

 occupied by eighteen or nineteen in the latter ; and the layer 

 of enamel is still more reduced in thickness. The disposition 

 of the plates presents the extreme degree of ' pectination ' 

 seen in the molars of any known species of elephant. The 

 differences observable in the vertical section are, however, so 

 inconsiderable, that, if regarded in this light merely, the 

 mammoth and the Indian elephant might j)ass for the same 

 species. But when the grinding surface of the crovsais of 

 their molars is examined, the transverse plates of enamel in 

 the Indian elephant are seen to be thicker and very closely 

 undulated, with the flexures deeply vn-inkled for the attach- 

 ment of the stratum of cement ; while in the mammoth the 

 crowns of the teeth are broader, the enamel plates are thinner 

 and less undulated, so much so that they are frequently 

 described as being transverse and straight. Such at least 

 is the character of the typical form of grinder in E. primi- 

 genius. This tooth measures ten inches in length, being 

 considerably under the size attained by the largest specimens 

 of the mammoth. It has not been deemed necessary to give 

 a figure of the section of an inferior molar, which differs in 

 no respect from the upper, more than in the case of the 

 existing Indian species. 



These are the principal modifications in the construction 

 of the teeth of the elephants. Although, at first sight, the 

 molars of E. insignis and E. primigenius appear to be very 

 different, the other intermediate forms constitute a series 

 which establishes a passage between them. The species 

 have been traced in a retrograde order, from the simpler to 

 the more complex forms, with the object of making the 

 descriptions more intelligible. It is interesting here to 

 observe how the. existing species are intercalated : the serial 



' The artist has drawn this figure re- 

 versed, as compared with the other sec- 

 tions, tlie worn end of the tooth being 

 to the right. The same remarli applies to 



fig. 6 rt of PL II., P. A.S. In PL I., P. A.S., 

 tlie Indian elephant has been named in 

 the reference E. Asiaticus (Blum.) instead 

 of E. Indiciis. 



