ELEPHAS PRIMIGENIUS. 77 



III.— DENTITION. 



The differentiation of three species of Elephants from remains found in the fossil state 

 in Great Britain was not fully admitted until the labours of the late Dr. Falconer, F.R.S., 

 became generally known. Professor Owen, whilst impressed with the remarkable 

 differences in the dental characters of remains referable to the Bleplias primigenius, was 

 not then (184G) prepared to consider them as indicative of more than one species.^ The 

 precise descriptions and beautiful illustrations of the varieties of molar teeth repre- 

 sented in the work of that illustrious comparative anatomist could not otherwise than 

 arrest the attention of palaeontologists, and of all others the distinguished naturalist 

 above mentioned, whose famous discoveries in the Sewalik Hills had made him familiar 

 with the dentition of extinct Proboscidea. 



The remarkable essay published by Dr. Palconer on the Species of Mastodon and 

 Elephant occurring in the Fossil State in Great Britain was commenced in 1857," 

 but he did not live to complete the latter part, referring to Elephas primigenms, and the 

 entire description of Elephas antiquiis is wanting.^ 



Every student of extinct forms of animal life is familiar with Falconer's classifica- 

 tion of the Proboscidea, based on the characters of their molar teeth, and of his methods 

 of constructing the ridge-formulae characteristic of the various sub-genera and species. 

 The terms " isomerous," " anisoraerous," and " hypisomerous," used by him to distin- 

 guish the specific characters, although not advanced as mathematically exact in every 

 case, being, as the author states, " liable to vary within certain limits dependent on the 

 race, sex, and size of the individual, but it may safely be asserted that the numbers 

 are never transposed or reversed, i. e. the younger tooth among the * intermediate 

 molars ' never normally exhibit in the same individual a higher number than the 

 older."* As an example, in the members of the sub-genus Eaeleplias, and notably the 

 Elephas primigenius and Elepihas Asiatkus, the ciphers of whose molars, he states, are 

 precisely alike in number, he formulates their ridges in upper and lower teeth thus : — 

 4-J-8+12 : : 12+16-|-24, showing that, with the exception of the first and ultimate true 

 molars, the others increase by increments of 4, or, as he terms it, by an " anisomerous 

 mode of progression." But, as will appear in the sequel, it is by no means easy to 

 determine what ciphers should even fairly represent the average number of ridges in certain 



^ ' British Fossil Mammals,' p. 243. 



2 ' Quart. Journ. Geol. Soc. of London,' vols, xiii, xiv, and xxi. 



3 In the ' Palaeoiitological Memoirs ' of the late Dr. Falconer the editor has appended certain "note- 

 book entries" to the end of the essay on Elephas primigenius. — ' Pal. Mem.,' vol. ii, p. 1/2. 



* 'Pal. Mem.,' vol. ii, p. 10. 



11 



