210 ON THE FOSSIL BONES OF PACHYDERMATOUS QUADRUPEDS. 



the two species by this sole difference, in his Manual, 6th edition, p. 

 121, and gave drawings of the two kinds of teeth in his abbildungen, 

 pi. 19. 



This difference consists in the form of the plates and in their num- 

 ber: it is observed from the germ. 



The germs of the elephant of India are lamellae, each of which is 

 formed of two surfaces almost parallel, and merely furrowed along their 

 length. (See pi. 9, fig. 5). In the elephant of Africa one of the sur- 

 faces (and oftentimes the two) produces in its middle, and along nearly 

 its entire height, an angular projection ; its furrrows are also much less 

 numerous. (^See pi. 9, fig. 6.) 



The result of this structure of the germs is, that the section of the 

 lamellae, when the tooth has been used, presents in the elephant of 

 India transverse narrow bands, of an equal breadth, the edges of 

 which, formed by the enamel, are very much festooned, and in the 

 elephant of Africa, lozenges, or bands broader in the middle than 

 at the two ends, whose edges when cut seldom exhibit well-marked 

 festooning. 



To this difference in form there is added one in the number : the 

 lamellae of the elephant of Africa being broader, less is required to 

 form a tooth of the same length ; nine or ten of these lamellae form 

 a tooth as large as thirteen or fourteen of the species of the Indian 

 elephant. 



It appears that these two species observe the same proportion in 

 the teeth of the same age, as in that of the same length. Thus on 

 comparing our skulls of the Asiatic with those of the African ele- 

 phant of nearly the same age, we find in the back teeth of the former 

 fourteen or fifteen lamellae, and in those of the others only nine or ten. 



Thus we liave never seen a tooth of the African elephant which had 

 more than ten lamellae, \A'hilst those of the Indian, according to M. 

 Corse, have them even as far as twenty-three, and we see some fossils 

 with twenty-four or twenty-five. 



2. — Differences relative to the Tusks. 



The tissue of the tusks presents no important differences. It always 

 presents on its transverse section those striae which go in an arc of" a 

 circle from the centre to the circumference, and in crossing form cur- 

 vilinear lozenges, which fill up its entire disc, and which are more or 

 less broad, and more or less perceptible to the eye. This character, 

 common to all the ivories of elephants, and depending immediately on 

 the pores of their pulpy nucleus, is not found in the tusks of anv other 

 animal. It is observed in all the fossile tusks, and it refutes the opi- 

 nion of Leibnitz*, adopted by some other writers, and even by Lin- 

 naeusf, that the horns of the mammoth might come from the morse, 

 (^trichechus rosmarus). The tusks of the morse appeared all composed 

 of small round grains heaped together. 



The size of the tusks varies according to the species, according to 

 the sexes, and according to the varieties j and as they increase durintr 



*Protogoea, § xxxiv, p. 26. f Syst. Nat. ed, xii, p. 49. 



