FALCONER ON THE AMERICAN FOSSIL ELEPHANT. 
65 
of palates with teeth, lower jaws, and detached molars of the Mam¬ 
moth, from different localities in the United States. The vast 
collection in the British Museum includes numerous remains of the 
species from Eschscholtz-Bay and Siberia, accessible for ready com¬ 
parison with British specimens. They all present, in the main, the 
same characters: a uniform ridge-formula; the same obtuse form 
of the lower jaw, and the same broad crowned molars, composed of 
closely compressed colliculi, with numerous digitations and at¬ 
tenuated uncrimped enamel-plates. The space within which the 
present communication is necessarily limited, prohibits my entering 
into the details of the comparison. One of the most essential points, 
is to determine the constancy of the ridge-formula, which, after the 
examination of a very large quantity of materials, I believe in the 
Mammoth to be thus : 
Milk molars. True molars. 
4, 8, ~ 12, 12, 16, 2U 
4, 8, 12, : 12, 16, 24. 
indicating above and below, the number of colliculi which nor¬ 
mally enter into the composition of the antepenultimate, penul¬ 
timate, and last milk-molars in the first groups, and in the second, 
those of the three true molars. The plates advance by quaternary 
increments in each series, bearing in mind, that the first true molar, 
although of larger dimensions, commonly repeats the number of 
ridges presented by the last milk-molar, and that the last true molar 
in all the Elephants and Mastodons is more composite than the 
others.* The formula in the North American Mammoth is identical 
with that of the Siberian and European forms. Exceptions are 
occasionally met, in which an unusual number of plates is presented. 
Eor instance, Dr. Warren figures and describes a last upper molar 
from Ohio, in which, including talons, the tooth presents thirty-two 
ridges.f But Mastodon Ohioticus , in which the dental characters 
consecutive ciphers 
* I take this opportunity of indicating a correction in the ‘ ridge-formula ’ of 
the subgeneric group Euelephas, given in my memoir “ On the Species of Mastodon 
and Elephant,” contained in Yol. xiii. of the Quarterly Journal of the Geol. So¬ 
ciety, 1857, p. 315. Instead of the cyphers 
4, 8, 12, 14, 18, 24, 
4, 8, 12, ’ 14, 18, 24-27, 
the series should have been : 
Milk molars. Tree molars. 
4, 8, 12, . 12, 16, 24, 
4, 8, 12, ’ 12, 16, 24-27. 
The correction, it will be observed, applies solely to the ciphers above and 
below, characteristic of the antepenultimate and penultimate true molars, the dis¬ 
crimination of which always presents the greatest difficulties, 
f On ‘ Mastodon giganteus,’ p. 163, PI. xxviii. fig. c. 
N. H. R.—1863. F 
