THE MAXTESE FOSSIL ELEPHANTS. 



constant, whilst also, as seen in the same figure, instead of being erect, several of the 

 last plates and posterior talon are reclinate, a condition common enough in the last true 

 molars of other species. The external surface of a plate when denuded of cement, 

 presents, as seen in Plate II. figs. 3 & 5, perpendicular ridges more or less parallel, 

 and always situated towards the middle of the plate, their number varying in plates of 

 the same molar ; however, as seen in fig. 3, they are more or less concurrent with the 

 central digitations. Their outline varies considerably, being either rounded or sub- 

 angular ; but there is usually one much larger than the others, with its inner surface 

 hollow and triangular, so as to form " the angulation," which is a prominent feature of 

 the disk when ground down below the digitations. 



Besides these prominent ridges there are numerous small and finely defined ribs 

 separated by inosculating channellmgs, which converge and become faint towards the 

 digitations, as seen in fig. 5. Again the outer surface of the enamel is marked by 

 transverse wrinkling or wavy puckerings, which are extremely fine in germ molars ; 

 whilst in teeth in wear they become rough and granulated, in order that the cement 

 may be firmly attached to their surfaces. The figs. 4 & 4 « display the interior surface 

 of a plate, against which the ivory is packed. Here the only feature on the enamel is a 

 series of vertical strife like the external channellmgs, with the above-mentioned " angular 

 expansion " forming a furrow with abrupt sides, sometimes extending up and down 

 in an unbroken or an irregular manner. It is situated, in upper molars, about the 

 middle ; and in lower, from the arcuation of their crowns, it is usually ex-central. Its 

 abutment on the macheerides of the enamel not only increases the triturating capabilities 

 of the crown-surface, but, as just remarked, it forms a conspicuous feature on all well- 

 worn disks. 



These channellings, puckerings, and angular expansions vary considerably ; the latter, 

 however, are always present at some time or other during the attrition of a plate, their 

 absence being usually noticed in newly invaded crowns, which, when half worn, often 

 display the " angulation " in a pronounced degree. The transverse section, as in fig. 7, 

 shows a granulated outline on the cement side of the enamel, which is caused by the 

 above-mentioned rugous channellings and wavy lines. These, in descriptions of the disks, 

 are named by Falconer " false or spurious crimping." I shall allude to the condition 

 frequently, using the expressions " false " or " famt " crimping according to the nicety 

 or obscurity of the appearance. 



It is evident therefore that the irregularities of the machserides of worn disks are 

 owing to the above conditions, whilst the digitations and their obliquity, together with 

 their intervening sulci, furnish the irregular and often excessive festooning of newly 

 invaded crowns. Whenever the enamel is very thick its sui-face-roughness is not so 

 well developed ; and even in thin-plated molars it is not always pronoimced. 



Besides these characters there is, especially in lower molars, a central expansion of 

 the disk, which increases when the wedge is being ground down to a, as may be supposed 



