484 



2755. A pair of tusks of a young Elephant. 



They are nearly straight, and obliquely abraded at the point. 



Presented by Mrs. Robinson. 



2756. One of the tusks of a young Elephant. 



It shows an abnormal form in the direction of its growth, being wreathed in two long 

 spirals : a fissure in the pulp-cavity leads to a longitudinal groove on the outer surface, where 

 the ivory has been incompletely formed. 



Mus. Brit. 



2757. One of the tusks of an older, and probably African, Elephant. 



It shows a similar abnormal spiral curvature. This specimen is figured and described in 

 Grew's ' MiLsceum Regalis Societatisj* 1681, p. 31. "A spiral or wreathed tusk of an Ele- 

 phant. Presented from the Royal African Company by Thomas Crispe, Esq. It is twisted 

 or wreathed from the bottom to the top with three circumvolutions, standing between two 

 straight lines. 'Tis also furrow'd by the length. Yet the furrows surround it not, as in the 

 horn of the Sea Unicorn ; but run parallel therewith. Neither is it round, as the said horn, 

 but somewhat flat. The top very blunt." Fig. tab. 4. 



Mus. Brit. 



2758. A transverse section of the base of the tusk of a young Elephant. 



It shows the smooth surface of the pulp-cavity and the longitudinally striated outer sur- 

 face. The contour is elliptic. On the cut surfaces may be discerned the decussating curved 

 striae characteristic of true ivory, an appearance which is due to its microscopic structure. (See 

 Owen's Odontography, p. 640.) 



Presented by Prof. Owen, F.R.S. 



2759. A transverse section of the tusk of an Elephant. 



Through long exposure this has partially separated into superimposed laminae. From a 

 nearly effaced inscription it appears to have been originally transmitted to the British Museum 

 as part of a Mammoth's tusk, found fossil ; and it is probably from a female of the Elephas 

 primiffenius. The inference as to the composition of ivory by superimposed and successively 

 excreted layers, founded upon such appearances as this and similar fossil tusks present, is 

 fallacious : a truer indication of the texture of ivory is afforded by the decussating curyed 

 lines or engine-turned pattern which may be seen on both the cut surfaces of this section. 



Mus. Brit. 



2760. Portions of several layers into which the tusk, probably of a Mammoth (Ek- 

 phas primigenius), has been resolved. Mm. Brit. 



2761. A section of the base of the tusk of an Elephant, in the substance of which a 



