16 MR. A. L. ADAMS ON THE OSTEOLOGT 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 (PI. I. fig. 13). It is worn not quite half down, so that the crimping of the machse- 

 rides, as in fig. 7, is pronounced. It is a 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 suflaciently 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 difier, 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 tlie 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 (PI. I. fig. 12), and its profile view (PI. VI. fig. 2), is by no means perfect 



