16 MR. A. L. ADAMS ON THE OSTEOLOGY OF 
being hollow in this specimen. As these, however, are all lower teeth, the occasional 
addition of a ridge is not uncommon; thus it may be that the normal number is seven, 
or, in other words, five plates and two talons. They are, however, slightly larger 
than No. 14 (fig. 8), yet doubtless of the same form. 
B Series.—An upper molar holding eight ridges in 2 inches is well shown in crown 
No. 60(P1. I. fig. 13). It is worn not quite half down, so that the crimping of the mache- 
rides, as in fig. 7, is pronounced. It isa broader tooth, however, with very thick plates, 
each being as much as 0°3 inch; indeed their size gives quite a character to the ridges. 
The posterior talon is a broad digitated splint, rising about the middle of the seventh 
ridge, the anterior talon being semicircular, and worn to the common base. 
The fragments Nos. 89, 97, & 85, of upper molars just commencing wear, are referred 
to this variety. Of other upper molars of B Series, or what might be called the thick- 
plated type, No. 104 (fig. 16) represents eight independent ridges in a space of 2:2 inches, 
followed by Nos. 76, 82,.77, & 54 of my collections in B. M. The last, represented in 
fig. 14, is the largest penultimate milk-molar, and contains eight ridges in 2-4 inches. 
None, excepting No. 82, are worn sufficiently to fully develop their rhomboidal disk, 
which, however, is beautifully shown on its crown. In regard to its posterior talon- 
shaped ridge, so often dwarfed in A series, it is well developed in all of the largest penul- 
timate milk-teeth ; and although convex in the above, it rises for the most part from the 
common base with the other collines, so as to be classed as a talon only on account of 
its more curving outline. 
The largest lower molar (fig. 14) is as large as small instances of the penultimate 
milk-molar of the African Elephant, which ordinarily contains the same number of 
ridges. It does not differ, however, from the other large specimens in its ridge-formula 
and crown-pattern. 
Summary.—From the foregoing I think it must be inferred that they at least repre- 
sent two elephants differing in size :—one of dwarf dimensions, holding ordinarily seven 
ridges in its upper teeth; and another, larger form, with eight ridges. The likelihood 
of an intermediate form is not at all clear. As regards crown-patterns, the same appear- 
ances prevail throughout A & B series. In newly invaded crowns there is much 
crimping; but when half-worn in the smallest, intermediate, and largest, as seen in 
fig. 8 and Nos. 6 & 82, we find the rhomb-shaped outline, with the angulation of 
Elephas antiquus, but there is faint instead of pronounced crimping. 
The thickness of the plates does not seem, unless in the largest molars, to be dia- 
gnostic, as we find thick- and thin-plated specimens among the smallest and intermediate- 
sized teeth. In the largest, however, it would seem to be general, with rugosities on 
the enamel of the posterior talon, and which we shall find are also prominently shown 
in the largest last milk-molars. 
The fragment of the lower molar, holding six ridges in a space of 1°5 inch, shown in 
jaw No, 41 (Pl. I. fig. 12), and its profile view (Pl. VI. fig. 2), is by no means perfect 
