132 



HAHDWICKE'S SCIENCE-GOSSIP. 



and form the two into seven folds, about five inches 

 in height. The folded cards should then be placed on 

 a table with their folds in a vertical direction, with 

 a space of about half an inch between the summits of 

 each ridge, and the intervening troughs or valleys 

 should then be filled to the level of the ridges with 

 fine sand or sawdust. If it be then assumed that the 

 hollows beneath the folds of the brown cardboard are 

 filled up with the same substance, the reader will 

 have a very fair model of a part of the grinding-tooth 

 of a true elephant ; a perfect tooth consisting only of 

 a greater number of similar folds. The folds of 

 brown cardboard which form the base of the tooth, 



Fig- 73- — Vertical section of a large upper grinding-tooth of the flat-headed 

 elephant, to show the structure of the teeth in the true elephants : a, cement ; 



t, enamel ; c, ivory. In the 

 more closely packed together. 



iving Indian elephants the folds are taller and 

 (After Falconer and Cantley.) 



the grinding surface a number of fine ridges, ad- 

 mirably adapted for trituration. In the Indian 

 elephant as many as twenty-four of these folds, or 

 plates, are contained in a single last grinder, while 

 the middle teeth contain from twelve to eighteen of 

 such plates. In ' the Sutledj elephant the number 

 of these plates is somewhat less, and their vertical 

 height is not so great ; from which it may be inferred 

 that in this respect the animal was somewhat lower 

 in the scale than its living Indian congener. In the 

 flat-headed fossil elephant the plates of the grinding- 

 teeth were even yet lower and thicker, as if the folds 

 of the cardboard had been shorter, and not folded 

 quite so close ; this type of tooth being 

 more like that of the existing African 

 elephant, which differs widely in this 

 respect from his Indian cousin. 



We now come to the consideration 

 of the intermediate elephants, of which 

 four species are known, and have been 

 respectively named Ganesa's elephant, 

 the round-headed elephant, the re- 

 markable elephant, and Clift's elephant. 

 These animals were to all intents and 

 purposes elephants ; having but two 

 tusks, and jaws of the same form and 

 structure as those of the existing spe- 

 cies ; their grinding-teeth are, hovv- 



;—/' 



ever, of a much simpler structure than 



/■/^ 



Fig. 74. — Vertical section of the last upper grinding-tooth of an intermediate 

 elephant: a, cement; b, enamel ; c, ivory. (After Falconer and Cantley.) 



correspond to the ivory of the elephant's grinder ; 

 the overlying white cardboard to the enamel, and 

 the sand or sawdust, to an external substance termed 

 cement. It will be .readily seen that if a horizontal 

 section be made of such a structure, the exposed 

 surface will consist [of layers or plates of the three 

 different substances arranged in the following se- 

 quence, viz. brown cardboard, white cardboard, 

 sand, white cardboard, brown cardboard ; this surface 

 corresponding to the worn surface of an elephant's 

 grinder, where the order of arrangement of the 

 different substances is the same, viz. ivory, enamel, 

 cement, enamel, ivory. The different degrees of 

 hardness of these three substances produce on 



those even of the flat-headed elephant, 

 the ridges being much fewer in number, 

 and lower in height ; their elevation 

 being indeed not more than two inches, 

 and the interval between their summits- 

 as much as an inch and a half. The 

 cement in the hollows between the 

 ridges is, moreover, present in much 

 smaller quantity, so that the hollows 

 or valleys themselves are more or less 

 completely open. In most of the inter- 

 mediate elephants the number of ridges 

 in the middle grinders is from about, 

 eight to eleven, and twelve or thirteen 

 in the last tooth ; but in Clift's elephant 

 the number is reduced to six in the 

 middle teeth, and to seven or eight in the last. From 

 this circumstance the reader will not fail to see that, 

 as regards their teeth, these elephants are on much. 

 lower grade than the true elephants, although there is 

 an almost complete transition from Clift's elephant,, 

 which is the lowest form, through the round-headed 

 and Ganesa's elephant to the simplest type of true 

 elephant, like the flat-headed species. 



Of the primitive elephants, or mastodons as they 

 are more generally called, there are six Indian 

 species, three of which have more complex grinders 

 than the others, and thus effect a regular transition 

 from the intermediate elephants to the latter. The 

 three species with the more complex teeth have beea 



