10 MK. A. L. ADAMS ON THE OSTEOLOGY OF 



same small form. In this specimen all the characters of the Elephant's tusk are well 

 shown, the " engine-turning " being especially distinct. 



3. First or PreantepenuUimate Milk-molar ; Second or Ante- 

 penultimate Milk-inolar. 



In all known species of the genus Elephas both the first and the second milk-molar, 

 theoretically, have two divergent fangs ; the only exceptions apparently are among the 

 Maltese fossil Elephants, which show a functionally developed second tooth with only 

 one straight fang, as seen in PI. I. fig. 6, and others referred to by Falconer, and 

 published in the sixth volume of the Society's ' Transactions '^ 



With reference to the theoretical first or preantepenultimate milk-molar, rarely 

 developed in either fossil or recent species, there is one very interesting specimen 

 in the British Museum. 



The African skull containing this condition is No. 7085 of the osteological catalogue. 

 It is the same referred to in the ' Fauna Antiqua Sivalensis,' pi. 14. fig. 4, left side, a, 

 and by Blainville in his ' Osteographie,' pi. 9. figs. 1, 2. The appearances of the 

 dentition are as follows: — The milk-incisor and its enamelled tip is just protruding 

 beyond the sheath, with a club-shaped -point as seen in the Zebbug fossil (PI. I. fig. 1), 

 the former being 1'4 inch in girth. In the Upper Jaw the second or antepenultimate 

 is in full wear, with one ridge of the next tooth invaded. The former is 0'8 by 0'7 inch, 

 and composed of three plates and two talons ; the latter is 2"3 by 1 inch, and is composed 

 of five plates and two talons ; behind all is the empty alveolus of the last milk-tooth. 



The Lower Jaw (Right) contains the antepenultimate and penultimate molars. 

 The former is in full wear, with three ridges of the latter invaded. The antepenulti- 

 mate is 0"8 by 0'4 inch ; its fangs axe furcate, with a pronounced depression or pressure- 

 mark below the crown posteriorly, as in the fossils to be described presently. The 

 penultimate is 2-2 inches by 1-1 inch, and made up of six plates and two talons. 



The Left Lower Ramus contains the first or preantepenultimate, composed of two 

 plates and two talons ; the length of the crown is 0-G5 by 0'4 inch. The antepenultimate 

 is also composed of two plates and two talons ; its length is 0-85 by 0-6 inch. The fangs 

 in both are divergent ; but the posterior of the preantepenultimate is more divergent 

 than either of the antepenultimate, and absolutely crosses the anterior fang of the 

 latter, which, like the other root, is inserted more perpendicularly. The penultimate 

 is of the same dimensions as that of the right ramus ; and the same number of ridges 

 are invaded. No sejdum divides the ^ire- from the antepenultimate, and the latter and 

 the penultimate ; so that the grinding-surface on the left side is not more extensive than 

 on the opposite. Indeed the three successive teeth are close together, whereas there 

 is a septum between the ante- and penultimate teeth in the right side. Thus the 

 additional tooth takes up the space of the ordinary septum. 



' Page 286, and pi. 53. fig. 2 ; see also Pal«ont. Mem. vol. ii. p. 297. 



