104 BRITISH FOSSIL ELEPHANTS. 
attaches itself to this tooth, as has been pointed out in connection with its predecessors in 
the dental series. 
Until Falconer’s differentiations established a ridge formula of® 16 ® for the second 
true molar of the Mammoth, none of his contemporaries or predecessors had estimated 
the number very definitely. 1 2 But the average number assigned by him is subject to 
numerous exceptions, and is apparently, as far as I have been enabled to observe, too 
high an expression. Falconer states, “ I have seen no authentic specimen of an 
upper penultimate of the Mammoth presenting more than sixteen or seventeen ridges. 
That exceptional cases do occur in which as many as eighteen may be seen is not 
improbable, but, I believe, that as holds in the existing Indian species the prevailing and 
normal number is sixteen.” 3 He also refers to the tooth described by De Blainville, 3 in 
which fourteen collines exist, and doubts if the molar belongs to the Mammoth. That a 
penultimate true molar of the Mammoth may contain this ridge formula is proven, it 
appears to me, by the following instances. 
Upper molars. —In the rich collection of molars belonging to the Mammoth lately 
obtained from the Oxford gravel, and now in the University Museum, is an upper and 
lower penultimate true molar, each containing® 14 ®. The upper is G-7x2\8 inches, 
and contains eight ridges in 3J. The other will be referred to presently. 
Another and smaller upper tooth, holding the same ® 14 x ridge formula in 5X3 
inches, and eight ridges in 3J, is preserved in the Museum of Practical Geology, Jermyn 
Street. It is from the lower brick-earths of Crayford on the Thames, and is interesting 
also on account of the thin enamel of the crown, as compared with that of the Ilford 
specimens, as will be referred to again presently. 
The two molars, No. 23,115, evidently of the same individual, from Maidstone, 
Kent, in the National Collection, show the ridge formula of ® 14 x in 7X2-|, and eight 
ridges are contained in 3'9 inches. That these teeth are penultimate true molars is at once 
apparent from their size and the characteristic declination of the posterior ridges, and 
the flat pressure mark on the last ridge and fang. The disks present the usual parallel, 
narrow, and uncrimped characters of the Mammoth. The enamel is thick, and the plates 
much digitated, as often prevails. It is noteworthy that several of the posterior plates 
present roughenings and irregularities, as if several additional ridges had been suppressed 
during development, and might, if unsupported by further data, be considered deformed 
teeth, but the other instances and examples in lower teeth, to be referred to immediately, 
appear to me sufficient to establish the not uncommon ridge formula of x 14 ® in second 
true molars. 
1 Owen states it “ may have from sixteen to twenty-four plates.” De Blainville mentions molars 
with fourteen, eighteen, and nineteen plates or collines. ‘Brit. Foss. Mam.,’ ‘Odontography,’ p. 666, and 
‘ Osteographie des Elephants,’ pp. 195, 357. 
2 Op. cit., vol. ii, p. 168. 
8 ‘Osteog. des Elephants,’ p. 195. 
